Verifying and mitigating oscillation in amplifiers

ABSTRACT

A method is provided for detecting and mitigating oscillation in a booster amplifier. The booster amplifier is configured to sample a signal being amplified to determine whether the booster amplifier is oscillating. In addition, the status of the booster amplifier can be verified based on the apparent signal levels of the signals being amplified. The gain of the booster amplifier is then adjusted in accordance with whether the booster amplifier is oscillating or as necessary to maintain gain that is compatible with the system within which the booster amplifier is operating.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No.13/593,246 filed on Aug. 23, 2012, which is a continuation in part ofU.S. Ser. No. 13/439,148, filed on Apr. 4, 2012, which claims thebenefit of U.S. Provisional Application 61/526,452 filed Aug. 23, 2011.The foregoing applications are incorporated by reference in theirentireties.

BACKGROUND

Booster amplifiers are bi-directional amplifiers used for increasing thesensitivity and power output of cell phones and other wireless devicesthat are communicating through them. The use of a booster amplifier,however, may disrupt cellular systems of both the network through whichthe device is communicating and other cellular networks that the deviceis not communicating through.

The adverse effects of a booster amplifier can result in a poweroverload situation, where excessive power overshadows other devices andcauses them to be dropped or disconnected. A booster amplifier can alsoincrease the noise floor, which decreases the sensitivity of a basestation. Increasing the noise floor often decreases the coverage area ofa base station and impairs cellular service. In addition, a boosteramplifier may begin to self-oscillate. A condition that results in noiseand that can cause interference in the cellular system.

In addition to the disruption of cellular systems, an improperlyfunctioning booster amplifier can cause a wireless device's signal, asreceived by base stations, to be weaker than necessary. This can resultin poor reception of the wireless device's signal by base stations.Under certain conditions, this could even inhibit a wireless device fromplacing or receiving calls.

With the introduction of newer cellular and wireless technologies, thereis a need to prevent devices operating in the various networks frominterfering in those networks. At the same time, there is a need toenhance the ability of devices to effectively communicate in theirrespective networks.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify at least some of the advantages and features of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only illustrated embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 illustrates an example of a booster amplifier operating in acommunication system;

FIG. 2 illustrates a generalized booster amplifier with a controlcircuit that controls gain level.

FIG. 3 illustrates an embodiment of a bi-directional booster amplifierconfigured to control the amplification of signals between at least twodevices;

FIG. 4 illustrates another embodiment of a booster amplifier;

FIG. 5A-5E illustrate examples of methods for handling oscillation in abooster amplifier or for reducing oscillation in a booster amplifier;

FIG. 6 illustrates an example of a method for determining an optimumgain for a booster amplifier;

FIG. 7 illustrates an embodiment of a system and method for setting anoptimum gain in a booster amplifier;

FIG. 8 illustrates an example of a flow diagram for setting the gain ofa booster amplifier operating in a network environment;

FIG. 9 illustrates another example of a flow diagram for setting thegain of a booster amplifier;

FIG. 10 illustrates an embodiment of a system and method forimplementing the flow diagrams illustrated in FIGS. 8 and/or 9;

FIG. 11 is a flow chart of an example method of managing oscillations ofa booster amplifier; and

FIGS. 12-14 are flow charts of example methods of determining anoscillation amplification factor margin of a booster amplifier.

DETAILED DESCRIPTION

A properly functioning booster amplifier should be transparent to awireless network such that base stations do not perceive any significantdifferences for either the case of a wireless device communicating byitself within the wireless network, or the wireless device communicatingwithin the wireless network through the booster amplifier. Additionally,it may be desirable for emissions from the booster amplifier to bewithin limits acceptable to wireless networks, even without a wirelessdevice communicating through the booster amplifier.

Embodiments of the invention may be discussed with reference to awireless device operating in a wireless network. Example wirelessdevices may include cell phones, personal digital assistants, smartphones, laptop computers, tablet computers, modems, or other networkenabled devices. One of skill in the art can appreciate that embodimentsof the invention can be applied to other wireless networks includingthose operating on various frequencies throughout the electromagneticspectrum. Wireless networks may include cellular networks as well asother wireless networks. References to cellular networks and cellularsystems are also applicable more generally to wireless networks andwireless systems.

A base station may be any suitable location where the wireless networkantenna and communications equipment is placed. A wireless networktypically has many base stations in operation. A base station typicallyincludes a transmitter/receiver, antenna tower, transmission radios andradio controllers for maintaining communications with wireless devicessuch as a cell phone or other wireless devices within a given range.Similarly, “a base station” may refer to one or more base stations. Awireless device may also be representative of other devices that maycommunicate through the booster amplifier. Embodiments of the boosteramplifier discussed herein, for example, may amplify signals transmitterand/or received by one or more wireless devices in communication withone or more base stations.

In the present disclosure, the term “reverse link” refers to thetransmission path of a signal being transmitted from a wireless deviceto a base station. In some embodiments, the reverse link may also bereferred to herein as an uplink. The term “forward link” refers to thetransmission path of a signal being transmitted from the base station toa wireless device. In some embodiments, the forward link may also bereferred to herein as a downlink. The phrases “reverse link signal,”“forward link signal,” “uplink signal” and “downlink signal” are notlimited to any particular type of data that may be transmitted between awireless device and a base station, but instead are simply used tospecify the direction in which a signal is being transmitted.

Some embodiments relate to amplifiers, including booster amplifiers,that enhance the ability of a wireless device such as a cellulartelephone (or other device configured to communicate over a wirelessnetwork) to communicate in a wireless network. Embodiments extend to anamplifier that adjusts the gain, dynamically in some embodiments, thatis applied to a wireless signal within the wireless network. Embodimentsfurther relate to systems and methods for managing at least one of basestation overload, noise floor protection, and self-oscillation as theyrelate to amplifiers such as booster amplifiers.

Some embodiments of a booster amplifier variably adjusts its gain asneeded. The ability to variably and/or automatically adjust the gainapplied to a wireless signal can prevent the booster amplifier fromgenerating emissions that may interfere with the operation of a wirelessnetwork within which the booster amplifier is operating, with otherwireless networks, or with the operation of the booster amplifieritself. Too much gain, for example, can cause the booster amplifier tooscillate, which may result in interference to the wireless network andmay adversely impact users of the wireless network. Also, too much gainmay unnecessarily increases the amount of residual noise at the basestations. Too little gain may interfere with the ability of the wirelessdevice to communicate in the wireless network. As previously stated,embodiments of the invention protect against at least one of poweroverload oscillation, and/or excessive noise floor increase.

Some embodiments consider parameters that may have an impact on theoperation of the booster amplifier when setting the booster amplifier'sgain. The booster amplifier includes circuitry, modules and/orcomponents (e.g., hardware, software, firmware, etc.) that determine anoptimum gain under various circumstances based on these parameters. Thebooster amplifier can be configured to determine an optimum gain bymitigating the effect of specific issues individually and/or multipleissues at the same time. The booster amplifier can determine an optimumgain to mitigate each of the issues that have been considered by thebooster amplifier. In one example, the booster amplifier generatespotential gains for each issue. These potential gains can then beharmonized to generate a final gain that may be optimum in light of allthe issues that are being mitigated.

Embodiments of the booster amplifier can be integrated with a wirelessdevice or connect with the wireless device either wirelessly or wired.The booster amplifier acts as an intermediary between a base station andthe wireless device. Signals generated by the wireless device areamplified and retransmitted by the booster amplifier. The boosteramplifier also receives signals from the base station and transmits theamplified signals to the wireless device after applying a gain to thereceived signals. In some examples, the gain may reduce the strength ofthe signal.

In some embodiments, the booster amplifier receives a first wirelesssignal from a base station via a first antenna and a second wirelesssignal from a wireless device via a second antenna. A control circuitanalyzes the inputs and/or outputs of the booster amplifier and adjustsa gain (or an amplification factor) in a manner that accounts for theparameters sensed using various inputs to the amplifier.

The adjusted gain is applied to the first and/or second wirelesssignals, and the resulting wireless signals are retransmitted via thefirst and second antennas to the base station and the wireless device,respectively. In some embodiments, the gain applied to the wirelesssignals in one direction (e.g., from the base station to the wirelessdevice) may be different from the gain applied to the wireless signalsin the other direction (e.g., from the wireless device to the basestation).

FIG. 1 shows an example communications system 100. The communicationssystem 100 may be a cellular telephone wireless network or otherwireless network. In this example, a booster amplifier 102 configured toamplify signals transmitted between a base station 106 and a device 104.The device 104 may be any type of wireless device. In a typical system,the booster amplifier 102 is located in close proximity to the device104 in comparison to the distance between the booster amplifier 102 andthe base station 106. The base station 106 transmits a signal 108 intothe surrounding air, which is attenuated for various reasons known toone of skill in the art as it travels outward from the base station 106.An antenna 110 receives the signal 108 and converts the radiated signalinto a conducted electrical signal.

The booster amplifier 102 amplifies the electrical signal andcommunicates the amplified signal to the device 104. In one example, thebooster amplifier 102 may retransmit the electrical signal from a secondantenna 112 as an amplified RF signal 114 to the device 104. Theamplified signal 114 is received by an antenna 116 of device 104, whichprocesses the signal and ultimately communicates the appropriate contentto a user of device 104.

As previously indicated, the booster amplifier 102 may be an integralpart of, or separate from, the device 104. The booster amplifier 102 mayalso be implemented in a cradle configured to hold the device 104. Forexample, the cradle may be mounted on a dash of a car and the device 104may be placed in the cradle. The communication between the cradle, whichmay include the booster amplifier 102, may be wired and/or wireless. Inaddition, signals to and from the device 104 may be communicated withthe amplifier 102 using a wired cable 118 and/or the antenna 112. Moregenerally, the booster amplifier 102 may be included in a differentform. When the booster amplifier 102 is used, for example, in a buildingor other area, the form may be adapted or configured for placement ormounting as appropriate for the location.

Similarly, the device 104 may communicate content to the boosteramplifier 102 by transmitting an RF signal from the antenna 116, whichis ultimately received by the antenna 112. The booster amplifier 102amplifies the received signal and retransmits the signal using theantenna 110. The transmitted signal is received by the base station 106,which may perform a number of operations on the signal, as determined bythe wireless service provider.

During operation, the booster amplifier 102 can dynamically amplifysignals transmitted to the base station 106 as well as signals receivedfrom the base station 106. The gain applied to the signals beingamplified can be dynamically adjusted over time and in accordance withvarious factors. For example, the gain may be set to account for or tomitigate potential issues that may arise in the wireless environment.The booster amplifier 102 may be configured to prevent the amplifieritself from interfering with the operation of the wireless system 100 orof the base station 106 or of other devices operating in the system 100or with other wireless systems that may be in operation.

For example, embodiments of the invention consider parameters that mayhave an impact on the operation of the booster amplifier 102 whensetting the booster amplifier's 102 gain. In particular, the operationof the booster amplifier 102 is monitored such that the boosteramplifier 102 does not oscillate. If oscillation is detected in thebooster amplifier 102, then the gain of the booster amplifier 102 isreduced or the booster amplifier 102 is turned off in order to eliminatethe oscillation and reduce the adverse effects of the oscillation.

Because it may be possible to confuse oscillation with validamplification, embodiments of the invention also distinguish betweenoscillation and valid amplification. By way of example only, a desirablesignal may be present when the device 104 is used to communicate in thesystem 100 or transmit/receive signals (e.g., a cellular phone call,Internet access, etc., are examples of when a desirable signal ispresent). When the device 104 is idle or not being used, a desirablesignal may not be present at the input to the booster amplifier 102. Itmay also be possible for oscillation to occur when amplifying a validsignal.

The booster amplifier 102 includes circuitry, modules and/or components(e.g., hardware, software, firmware, etc.) that determine an optimumgain or optimum configuration (including off) under variouscircumstances including oscillation. The booster amplifier 102 can beconfigured, for example, to reduce, change, or eliminate the gainapplied by the booster amplifier 102 when oscillation is detected orwhen other issues are detected.

FIG. 2 illustrates a generalized directional booster amplifier 202 (anexample of the booster amplifier 102) configured for producing anoptimal gain level. The booster amplifier 202 is unidirectional in thisexample in the sense that gain is only controlled in the reverse linkdirection or in the forward link direction. The booster amplifier 202 isconnected to a first antenna 210, which is configured to receive asignal. The first antenna 210 converts the received signal into anelectrical signal. The electrical signal is received by a variable gainmodule (VGM) 216, which applies an amplification factor to theelectrical signal. In one embodiment, the electrical signal iscommunicated via a second antenna 212, which transmits the adjustedelectrical signal as an RF signal, to be received by one or morewireless devices, which may include handsets.

The variable gain module 216 is controlled by a control circuit 214. Thecontrol circuit 214 receives the electrical signal from the firstantenna 210, and based on, by way of example, the properties of theelectrical signal and/or other parameters, determines an optimalamplification factor that should be applied to the electrical signal.The control circuit 214 provides a control signal to the variable gainmodule 216. The control signal instructs the variable gain module 216 asto the amplification factor that should be applied to the electricalsignal.

Many factors or parameters may be accounted for when calculating therequired amplification factor. Factors include, by way of example andnot limitation, the level or strength of the electrical signal andwhether there is any indication that the booster amplifier 202 isoscillating or overloading a wireless network in which the boosteramplifier 202 is operating in any way or affecting other wirelessnetworks.

The amplification factor, in one embodiment, can be a multiplier that isapplied to the electrical signal. The amplification factor can result ineither an amplified or attenuated output signal. In other words, wherethe absolute value of the amplification factor is less than one, theamplified adjusted signal will have lower amplitude than the originalelectrical signal. Conversely, when the absolute value of theamplification factor is greater than one, the amplified adjusted signalwill have greater amplitude than the original electrical signal.

The control circuit 214 is an example of a processor that can be usedfor processing inputs. As described in more detail below, the controlcircuit 214 may also receive other inputs, which are examples of factorsor parameters that are used when setting the gain to be applied to theelectrical signal. The inputs can be derived from the input signal orreceived from other sources.

FIG. 3 illustrates one embodiment of a bi-directional booster amplifier302 (an example of the booster amplifier 102) configured to control theamplification of wireless signals being transmitted between a basestation and a device (or other wireless signals transmitted between twodevices or apparatus). In the booster amplifier 302, a wireless signalis received from a base station at the antenna 310 and is passed to botha control circuit 314 and a variable gain module 316. Control circuit314 controls the amplification factor of the variable gain module 316.The amplified signal may be connected to a second antenna 312, whichtransmits a wireless signal to a device.

Bi-directional booster amplifier 302 is also configured to receivesignals from one or more devices (e.g., wireless devices), amplify thosesignals, and retransmit the amplified signals to a base station. Asignal from a device may be received by antenna 312. The signal isrouted to a second variable gain module 304, which applies anamplification factor to the signal. The amplification factor isdetermined and controlled by control circuitry 314.

In order to allow antennas 310 and 312 to simultaneously transmit andreceive signals, duplexers (DUP) 306 and 308 are provided by way ofexample. A duplexer is defined as an automatic electrical routing devicethat permits simultaneous transmitting and receiving through a commonpoint. More generally, a duplexer is a three-port device with one commonport “A” and two independent ports “B” and “C.” Ideally, signals arepassed from A to B and from C to A, but not between B and C. Forexample, the duplexer 306 receives an RF signal from a base station andconverts the signal into a first electrical signal, which is routed tothe inputs of the variable gain device 316 and the control circuitry314. The duplexer 306 may also receive a second electrical signal fromthe output of the variable gain module 304, and causes this signal to betransmitted as an RF signal via the antenna 310.

The control circuitry 314 may be configured to accomplish variousobjectives when determining the amplification factors to be applied tothe variable gain modules 304 and 316. Exemplary objectives include, butare not limited to, i) setting the power level at which the signals aretransmitted at a sufficient level to ensure that the signals reach atarget destination; and ii) ensuring that the signals transmitted fromthe booster amplifier 302 are transmitted at a power level thatsubstantially eliminates the interference that would otherwise beintroduced into the surrounding wireless network.

First, the control circuitry 314 establishes the amplification factorsof the variable gain modules 304 and 316 so that the resultant signalsare transmitted with sufficient power to adequately reach a targetdestination, such as a device or a base station while not exceedingregulatory or other (e.g. industry) established power limitations. Whenthe wireless signal received at the antenna 310 has undergonesignificant attenuation, e.g., when the target destination is located along distance away from the booster amplifier 302, the amplificationfactor is increased. Conversely, when the wireless signal received atthe antenna 310 is at a sufficiently high level, a lower amplificationmay be established for variable gain modules 316 and 304. Thus, theamplification factor or gain for various conditions can be determined byconsidering these parameters.

Second, the control circuitry 314 ensures that the signals transmittedfrom the booster amplifier 302 are transmitted at a power level thatsubstantially reduces or eliminates the interference that wouldotherwise be introduced into the surrounding wireless network. Manywireless networks, such as CDMA systems, are configured such that thepower level transmitted by each device in the network is determined bythe base station. When communication between a device and a base stationis initiated, a “handshake” occurs between the device and base station,and the base station instructs the device as to the power at which thedevice should transmit. If the base station determines that the signalfrom the device is too strong, it will instruct the device to reduce thepower level of the transmitted signal. The CDMA system is designed sothat all of the signals coming into the base station are ofapproximately the same power. If one signal arrives at the base stationat a power level that is significantly higher than the others, it canpotentially overpower the base station and cause interference with theother devices in communication with the base station.

Therefore, the control circuitry 314 may determine the maximum amplitudeor power level that can be transmitted by antenna 310 to substantiallyeliminate interference. Interference is considered to be substantiallyeliminated, in one example, when signals are transmitted from thebooster amplifier 302 without causing harmful effects to the surroundingwireless network. For example, interference is substantially eliminatedwhen the signals are transmitted without overpowering the base station,or otherwise interfering with other devices within the wireless networkin a way that degrades their performance. The control circuitry 314 mayestablish the amplification factors applied to variable gain modules toeither attenuate or amplify the electrical signals in order to achievethis objective.

The determination of the amplification factor values may be dependent onwhether the signals received from the base station via antenna 310exceed a threshold (also referred to herein as a threshold level orthreshold value). The threshold value may be a predetermined set value,or may be a variable that is not established until the control circuitry314 makes a determination. For example, if after analyzing the strengthof the signals received via antenna 310, the control circuitry 314determines that the signal attenuation between the booster amplifier 302and the target base station or device is substantial, the controlcircuitry 314 may establish higher threshold values than if the basestation signal was less attenuated. The higher threshold values wouldallow a greater amplification factor to be applied to the signals sothat the transmitted signals will reach their target destination.Because of the substantial distance over which the signals musttraverse, the signals will arrive at the target destination (e.g., abase station) without exceeding an appropriate power level, and willtherefore not overpower the base station or cause substantialinterference with signals transmitted from other devices.

In the embodiment of FIG. 3, the amplification factors applied to thevariable gain modules 316 and 304 may both be determined based on theattributes of the signal received from a base station via the antenna310. The input signal from the base station is received by the controlcircuitry 314 from the antenna 310 at the connection 318, and radiatedto a device via antenna 312. The control circuitry 314 can make a numberof determinations based on the attributes of the base station signal.First, the control circuitry 314 can determine the amplitude level ofthe signal from the base station. Based on the amplitude level, thecontrol circuitry 314 can determine an adequate amplification factor forthe variable gain module 316 to enable communication of the receivedsignal to a device. Second, the amplitude of the signal received fromthe base station is also an indicator of the amplitude required tosuccessfully transmit a signal back to the base station via the antenna310. For example, if the control circuitry 314 measures low amplitude ofthe first electrical signal, it is likely that the signal transmitted bythe base station has been substantially attenuated between the basestation and the booster amplifier 302. Therefore, it can determine theamplification factor required by the variable gain module 304 so thatthe second electrical signal originating from the device isretransmitted with sufficient power to reach the base station (withinallowable regulatory and/or other established power limitations).

The control circuit 314 may also receive additional input. The controlcircuit may receive an input signal from the connections 320, 322, and324 which correspond, respectively, to the input signal from the device(which may be received wirelessly), the output signal of the VGM 316,and the output signal of the VGM 304.

FIG. 4 generally illustrates another embodiment of a booster amplifier400. FIG. 4 illustrates an example of the booster amplifier 400 in thecontext of detecting oscillation and is used to illustrate aspects ofoscillation mitigation in the booster amplifier 400.

The booster amplifier 400 may include one or more stages (including afinal power stage and one or more preceding stages) and may beconfigured to amplify signals transmitted to a base station as well asreceived from the base station. When embodiments of the inventionoperate in the reverse link path and the forward link path, thecircuitry can be adapted to account for the signal path. For example,one amplifier (or chain of amplifiers) may amplify in the reverse linkdirection while another amplifier (or chain of amplifiers) may be usedto amplify in the other direction. Some components can be shared, suchas a microcontroller 414 (which is an example of the control circuit314). The microcontroller 414 may have the ability to controlamplification in either the reverse link or forward link direction.Suitable hardware may be provided in order to route these signals asnecessary within the booster amplifier 400. Alternatively, themicrocontroller is an example of control circuitry. The operations ofthe microcontroller 414 can be implemented in hardware and/or software.

In this example, an input 406 (e.g., a signal from a base station orfrom a wireless device) is provided to a preamplifier 402. An output ofthe preamplifier 402 usually contains amplified input signals (examplesof desired signals) and amplified thermal noise such as amplifiedbroadband thermal noise. By way of example only, in the 800 MHz Cellularband, the reverse link bandwidth could be from 824 to 849 MHz, and inthe 1900 MHz PCS band, the reverse link bandwidth could be from 1850 to1910 MHz.

The output of the preamplifier 402 is provided to the amplifier chain404. The oscillation detector 410 is configured to detect or sample anoutput of the amplifier chain 404. Alternatively, the oscillationdetector 410 can sample the signal at any point in the amplificationchain 404 including before and/or after the signal is operated on by theamplifier chain 404. In this example, the oscillation detector 410 maysample the output of the amplifier chain 404, although the oscillationdetector 410 may also sample the signals received and/or transmitted bythe amplifier 400 at other locations or at other times as previouslystated. In addition, the oscillation detector 410 may be configured tooperate with specific frequencies (e.g., the cellular band). Further,the preamplifier 402 may include a filter that restricts or controlswhich frequencies or bands are passed.

During oscillation detection, the oscillation detector 410 may samplethe output of the amplifier chain 404 a multitude of times over apredetermined time period. By way of example, the output may be sampledabout 100 times over a short period of time such as 3 milliseconds. Oneof skill in the art, with the benefit of the present disclosure, canappreciate that the different numbers of samples can vary and can betaken over different periods. For example, approximately 100 samples canbe taken over 5 milliseconds. The number of samples and the time overwhich the samples are taken can vary. In addition, the samples can betaken continuously or at predetermined intervals. In one embodiment,samples are taken continuously and a time window can be applied to thesamples for evaluating the samples. A 3 millisecond window, by way ofexample, can be applied to the samples taken by the oscillation detector410. By continuously taking and evaluating samples, the status (e.g.,oscillating or not oscillating) of the booster amplifier 400 can berepeatedly evaluated.

The samples taken by the oscillation detector 410 may be provided to themicrocontroller 414. The microcontroller 414 can then evaluate thesamples to determine the status of the amplifier 400.

In many wireless networks (e.g., CDMA, GSM, LTE, WiMAX), there is a highpeak to average power ratio (PAPR) (e.g., 5 to 10 dB in some examples).Oscillation, in contrast, in the booster amplifier 400 has asubstantially lower peak to average power ratio value becauseoscillation saturates the amplifier and compresses the signal. In thiscase, the PAPR may be closer to 0 dB, which may indicate a carrier oroscillation.

Thus, the microcontroller 414 can determine the PAPR and determinewhether the booster amplifier 400 may be oscillating using samples ofthe signal over a certain time period. In one example, if the PAPRexceeds a threshold level, then the microcontroller 414 determines thatthe booster amplifier 400 is not oscillating. If the PAPR is below thethreshold value, then the booster amplifier 400 may be oscillating. Insome examples, additional processes may be performed to verify theoscillation status before the gain is actually reduced or before thebooster amplifier 400 is shut down. These processes may be performed inorder to prevent any use of the device from being unnecessarilyinterrupted. In other words, the gain may be reduced first when adesirable signal is being amplified and oscillation is detected. In someembodiments, the threshold to which the PAPR is compared may bedetermined based on the characteristics of the wireless network in whichthe booster amplifier 400 operates. In particular, the threshold may bedetermined based on the PAPR for the wireless signals, e.g. the forwardlink and reverse link signals within the wireless network. For example,the booster amplifier 400 may operate in a wireless network thatsupports CDMA signaling. The CDMA signaling may have a PAPR of 5 or 10dB. The threshold value may be selected to be below the CMDA signalingPAPR but high enough to determine oscillations. For example, thethreshold may be selected as 1, 2, 2.5, or 3 dB.

When oscillation is detected, the gain of the booster amplifier 400 isreduced or the booster amplifier 400 is turned off using anamplification control circuit 412. The microcontroller 414 communicateswith the amplification control circuit 412 to control the gain of theamplifier chain 404 and thus the booster amplifier 400 as necessary toeliminate the oscillation. The gain can be gradually reduced, reduced insteps, or the like. If oscillation is not present, normal operation maybe resumed by the booster amplifier 400, which may include dynamicallyadjusting the gain of the booster amplifier 400. In one embodiment, theability of the booster amplifier 400 to dynamically adjust the gain maybe restricted or reduced when the output of the amplification controlcircuit 412 indicates that the booster amplifier 404 is off or hasreduced gain. The amplification control circuit 412, in other words, mayhave control that supersedes other components of the booster amplifier400. The ability to dynamically adjust the gain, along with othermethods disclosed herein, may be implemented in hardware, software,firmware, or any combination thereof.

Embodiments of the invention can reduce the effect of oscillation. Thebooster amplifier 400 is controlled by determining whether oscillationis present. When the booster amplifier 400 is being used to amplify adesirable signal, the booster amplifier 400 is enabled to operatenormally. If oscillation is detected even when amplifying a desirablesignal, the gain may be reduced as discussed herein.

The proper gain of the booster amplifier 400 can be achieved gradually,for example when oscillation is detected, by a variable attenuator or bychanging a bias voltage applied to an amplifier (e.g., to the amplifierchain 404) within the booster amplifier 400.

FIG. 5A illustrates an exemplary method for handling or detectingoscillation in a booster amplifier. The method 500 may also be used as aprecursor to identify a potential oscillation that is then verified inanother manner. This can eliminate false positives that may occur whenthe status of the booster amplifier is either based on signal samplestaken over a short time frame, or based upon a signal with a low PAPR.The methods of FIG. 5A (as well as the methods of FIGS. 5B-5E) may beperformed by detection unit or controllers in a booster amplifier, suchas the oscillation detector 410 and/or the microcontroller 414 of FIG.4.

A method 500 for reducing booster amplifier noise may begin by sampling502 a signal being amplified in the booster amplifier. The sampling maybe continuous in one example or may occur periodically. The samples canbe taken at any point in the booster amplifier, such as in an amplifierchain in the booster amplifier.

The method 500 then analyzes 504 the samples over a predetermined timeperiod. Analyzing the samples can be done by applying a time window tothe samples. In some embodiments, the time window may be stored inmemory. The samples can be stored, for example, in a rotating buffer.The samples may be analyzed to determine at least a PAPR.

The method 500 then determines 506 a status of the booster amplifier. Ifthe PAPR is below a threshold, it may be determined 508 that oscillationmay be occurring in the booster amplifier and the booster amplifier'sgain may be adjusted accordingly. For example, the gain may be reducedin stages, an amplifier or amplifier chain within the booster amplifiermay be turned off, or the like. If PAPR exceeds a threshold, it may bedetermined 510 that oscillation is not occurring. In these and otherembodiments, the booster amplifier may be allowed to operate normally.Often, when oscillation is determined to be occurring, the gain of thebooster amplifier is reduced until the effects of oscillation areremoved at which point the booster amplifier may be allowed to resumenormal operation at reduced gain or normal gains.

In some embodiments, when determining 506 the status of the boosteramplifier, a certain number of samples within a predetermined amount oftime are averaged. The peak value of the samples can be identified fromthe samples and the average of all the samples is then determined. Theresulting PAPR is then compared to a threshold value to determine thestatus of the booster amplifier. The status of the booster amplifier maybe oscillation when the PAPR is less than the threshold value and thestatus is normal when the PAPR exceeds the threshold value.

The samples in a given window or predetermined amount of time may beused to determine one or more signal ratios or power ratios including,by way of example only, a PAPR, a peak to peak power ratio, or a changein sample power levels.

More generally and by way of example and not limitation, examples ofsignal or power ratios include peak to average power ratio, a change insample power levels for a signal, a peak to minimum power ratio, peak toaverage power ratio, among others. One or more of these power ratios canbe used to determine the status of the amplifier. For example, eachratio can be compared to a threshold or predetermined value (this may bea different predetermined value for different power ratios). The resultof the comparison can indicate whether the status of the amplifier isoscillation or normal. In one example, the status may be verified byanother procedure.

In determining the peak to peak power ratio, the ratio may be determinedfrom samples that may include adjacent peaks, multiple pairs of adjacentpeaks, an average determined from multiple pairs of adjacent peaks,non-adjacent peaks, or the like or any combination thereof. A change insample power levels may be determined from the samples. A peak tominimum power ratio can be determined from samples that include variouscombinations of peaks and minimum values. The signal ratio in thisexample may include an analysis of multiple pairs of adjacent samplesand the change in power levels from the multiple pairs of samples can beaveraged.

The status, determined at 506, may be determined using one or more ofthe signal ratios. Of course, the status can be determined using onlyone of the signal ratios and there is no requirement that more than onesignal ratio be used to determine the status of the amplifier.

The relationship between the signal ratio and a threshold or apredetermined value can be used by the controller to determine whetheroscillation is occurring in the booster amplifier. One of skill in theart can appreciate that the predetermined value can be selected suchthat oscillation can be determined with the signal ratio is less than,greater than, equal to or greater than, equal to or less than, or thelike, than the predetermined value.

For example, if the controller determines that oscillation is occurring(the status is oscillation) when the signal ratio is below apredetermined value or threshold, then the controller may reduce thegain, turn off amplifiers within the booster amplifier (or any one ofthe stages of amplifiers), or the like. Often, the gain is controlleduntil the effects of oscillation are removed at which point the boosteramplifier may be allowed to resume normal operation. In this context,the signal ratio is continually reevaluated in order to determine whenthe oscillation has been eliminated or controlled. Monitoring the signalratio (or the signal ratios) provides an effective means to determinewhen the booster amplifier is allowed to resume normal operation.

When determining the status of the booster amplifier, a certain numberof samples within a predetermined amount of time may be averaged. Thepeak value of the samples can be identified and the average of all thesamples can also be determined when the signal ratio is the PAPR. Theresulting PAPR is then compared to a threshold or predetermined value todetermine the status of the booster amplifier. The status is oscillationwhen the PAPR is less than the threshold value and normal when the PAPRis equal to or exceeds the threshold value. Alternatively, an averagePAPR that is obtained by averaging the PAPRs associated with multiplewindows may also be used in determining the status of the boosteramplifier.

Similarly, other signal ratios can be used to determine the status ofthe booster amplifier. The peak to peak power ratio for samples in atleast one window or the change in sample power levels in at least onewindow are also signal ratios that can be used to determine the statusof the booster amplifier as illustrated in FIG. 5.

During operation (or at another time such as evaluation or testing), thegain of the booster amplifier may be increased to a level above thecurrent operating gain where such an increased level is whereoscillation begins. This enables a margin between the operating gain andthe oscillation point to be determined. In addition, this may be usefulduring operation of the device since the booster amplifier may be ableto estimate how much gain can be increased before oscillation occurs inthe booster amplifier. If the margin varies in operation due to actualoperating conditions, embodiments of the invention may determine thestatus of the booster amplifier independently of using the margin.

When it is determined that the amplifier is oscillating or that thestatus is oscillation at 508, some embodiments may perform furtherroutines to confirm that the booster amplifier is oscillating. Forexample, a short time window of samples may indicate that the boosteramplifier is oscillating when in fact, the booster amplifier is notoscillating. In other words, the booster amplifier may or may not betreated as oscillatory when the status is determined at 508 when thePAPR is less than the threshold value.

FIGS. 5B-5E illustrate further examples of methods for reducingoscillation in a booster amplifier. The methods illustrated in FIGS.5B-5E, or portions thereof, can also be combined with the method of FIG.5A to determine if a booster amplifier is oscillating, to preventoscillation in the booster amplifier. Some of the elements illustratedin FIGS. 5B-5E may occur prior to, during, and/or after the elementsillustrated in FIG. 5A. For example, receiving a downlink signal,receiving an uplink signal, and measuring aspects of these signals(e.g., input power) may be performed continuously or repeatedly by theamplifier. These values or measurements may be used in determining thestatus of the amplifier.

FIG. 5B illustrates a flow diagram for a method 520 of reducingoscillation in a booster amplifier. A booster amplifier may include oneor more antennas. A first antenna may be configured to communicate witha device and a second antenna is configured for communication with abase station.

Method 520 includes receiving 522 a downlink signal at the boosteramplifier from a base station via a first antenna, and receiving 524 anuplink signal from a device via a second antenna. The downlink and/oruplink signals are analyzed 526 to determine the presence of or confirman oscillation created by the booster amplifier. As previously stated,this determination may be confirmed after the status of oscillation isdetermined based on the PAPR.

If an oscillation is detected, the amplification factor may be adjusted528 in a manner that substantially reduces the presence of theoscillation. In some embodiments, control circuitry (such as controlcircuit 314) may perform the analysis of the downlink and/or uplinksignals and the adjustment of the amplification factor. In oneembodiment, oscillation is considered to be substantially reduced whenthe presence of oscillation is reduced to a level that does notintroduce interference into the surrounding wireless network.

In one embodiment, analyzing at 526 the downlink and/or uplink signalsincludes measuring a signal level (e.g., input power) of the downlinkand/or uplink signals. The measured signal levels may be compared topredetermined values. The predetermined values may be selected based onvalues that, if exceeded by the downlink and/or uplink signals, islikely to be indicative of an oscillating condition within theamplifier.

In one embodiment, where the predetermined value is exceeded, theamplification factor is reduced by an amount necessary to substantiallyreduce the oscillation. For example, the amplification factor may beincrementally reduced until the downlink and/or uplink signals fallbelow the predetermined value. The downlink and uplink signals may beassociated with different predetermined values.

Alternatively, the amplification factor may be automatically reduced toa zero value in the event that the signal level of the downlink and/oruplink signals exceeds the predetermined value. On the other hand, ifthe predetermined value is not exceeded, the amplification factor may beestablished so as to produce first and second amplified wireless signalsthat are strong enough to be successfully transmitted to the device andthe base station, without increasing noise at either the base station orthe device beyond a tolerable limit. In other words, the amplificationfactor may be increased to a value that allows signals to be transmittedbetween the device and the base station without poor reception ordropped calls.

Method 520 further includes applying 530 the adjusted amplificationfactor to the uplink and downlink signals. The adjusted amplificationfactor may be applied to the signals using variable gain modules. Asdescribed above, the amplification factor may actually include a firstand second amplification factor, where the first amplification factor isapplied to the downlink signal, and the second amplification factor isapplied to the uplink signal.

Method 520 also includes transmitting 532 the amplified uplink signal tothe base station via the first antenna, and the amplified downlinksignal to the device via the second antenna.

FIG. 5C illustrates a flow diagram for a method 540 performed by acontrol circuit for use in a booster amplifier. The booster amplifierincludes first and second antennas and at least one variable gainmodule. As described herein, the booster amplifier is configured for theamplification and transmission of cellular or other wireless signalsbetween a device and a base station. The method 540 includes analyzing542 the wireless signals to determine the presence and/or degree ofoscillation within the booster amplifier. Based on this analysis, thecontrol circuit makes the determination 544 of whether an oscillation isdetected at a degree that exceeds a predetermined value.

The predetermined value may be selected to represent a degree ofoscillation that if exceeded, produces a level of interference into asurrounding cellular or wireless network. If it is determined that thedegree of oscillation exceeds the predetermined value (i.e., the degreeof oscillation is likely to generate sufficiently adverse interference),the amplification factor may immediately be set 546 to a zero value. If,on the other hand, it is determined that the degree of oscillation isdetected at a degree that does not exceed the predetermined value (i.e.,the degree of oscillation is either negligible or relatively minor, thuscausing no interference or relatively mild interference), theamplification factor may be repeatedly decremented 548 until theoscillation is substantially reduced.

Finally the control circuit instructs 550 at least one variable gainmodule to apply the resultant amplification factor to the wirelesssignals. In some embodiments, a control circuit may instruct variablegain modules as to what amplification factor to apply to the wirelesssignals.

In one embodiment, if it is determined that the booster amplifier doesnot have any significant degree of oscillation, method 540 may furtherinclude establishing the amplification factor so that the retransmittedwireless signals have sufficient power to be transmitted to the basestation and/or device.

FIG. 5D illustrates one embodiment of a method 560 for detecting andsubstantially reducing oscillation in a booster amplifier. A cellular(or wireless) signal is received 562 by a first antenna. The wirelesssignal is amplified 564 by an amount determined by a first amplificationfactor. The resultant amplified wireless signal is transmitted via asecond antenna to a target destination, such as a device or basestation.

After the wireless signal is received 562 by the first antenna and whilethe first amplification factor is being applied to the wireless signal,the level of the wireless signal is measured 566, thereby acquiring afirst signal level. The first signal level is recorded, and then asecond amplification factor, which is less than the first amplificationfactor, is applied 568 to the wireless signal. In one embodiment, thesecond amplification factor is approximately a zero value (e.g., thepower amplifier within the booster amplifier amplifying the wirelesssignal may be turned off or disabled). In some embodiments, the secondamplification factor is approximately one or greater than one so thatthe wireless signal passes through the booster amplifier with little orno amplification.

While the second amplification factor is being applied to the wirelesssignal, the level of the wireless signal is measured again 570, therebyacquiring a second signal level. The second signal level is compared 572to the first signal level. If the second signal level is significantlyless than the first signal level, then it is determined that the use ofthe first amplification factor is likely causing an oscillatingcondition to occur. Therefore, the first amplification factor is reduced576 by a predetermined amount, and the process may be repeated until thefirst amplification factor is reduced by a sufficient amount toeliminate the oscillating condition. However, if the second signal levelis not significantly less than the first signal level, it is likely thatan oscillating condition does not exist while first amplification factoris applied to the wireless signal. Therefore, the first amplificationfactor remains unchanged 574, and the process may be repeated.

FIG. 5E illustrates another method 580 for detecting and substantiallyreducing an oscillating condition within a booster amplifier. Ingeneral, the method 580 includes the process of measuring 582 and 588 awireless signal level and comparing 584 and 590 the wireless signallevel to one or more threshold values. The amplification factor appliedto the wireless signal is adjusted 586 and 592 based on the results ofthe comparisons. The results of multiple comparisons are analyzed 594 inorder to detect a pattern that indicates that the presence of anoscillation is likely, and the amplification factor applied to thewireless signal is adjusted 596 in order to eliminate the oscillatingcondition.

In particular, and in one exemplary embodiment, after a wireless signalis received via an antenna and an amplification factor is applied to thewireless signal, the level of the wireless signal is measured 582 inorder to determine 584 whether the wireless signal exceeds a predefinedmaximum threshold value. If the signal level of the wireless signal doesnot exceed the maximum threshold value, the method 580 continuesmeasuring 582 the wireless signal and comparing 584 the signal to themaximum threshold value.

In the event that the signal level of the wireless signal exceeds themaximum threshold value, the method 580 reduces 586 the amplificationfactor applied to the wireless signal. Following the reduction of theamplification factor, the method 580 again measures 588 the signal levelof the wireless signal. The method 580 then compares 590 the new signallevel to the maximum threshold value and to a predetermined minimumthreshold value. If the signal level still exceeds the maximum thresholdvalue, the method 580 will continue to reduce 586 amplification factorapplied to the wireless signal until the signal level no longer exceedsthe maximum threshold value. If the signal level measured at 588 fallsbetween the maximum threshold value and the minimum threshold value, themethod repeats itself, starting with the measurement at 582. However, ifthe signal level measured at 588 falls below the minimum thresholdvalue, the amplification factor applied to the wireless signal isincreased by a predetermined amount.

Finally, the results of the comparisons and/or the adjustments made tothe amplification factor are analyzed 594 in order to determine if anoscillating condition likely exists. In one embodiment, the measuredsignal levels are analyzed in order to detect a pattern that mayindicate the presence of an oscillation.

For example, in one exemplary embodiment, the measured signal levels areanalyzed in order to detect an alternating pattern, where themeasurements of the signal levels alternate between exceeding themaximum threshold level and falling below the minimum threshold level.Therefore, an oscillation is identified if the signal level recordedduring a first measurement exceeds the maximum threshold level, thesignal level recorded during a second measurement falls below theminimum threshold level, and the signal level recorded during a thirdmeasurement exceeds the maximum threshold level. Likewise, anoscillation is also identified if the signal level recorded during afirst measurement falls below the minimum threshold level, the signallevel recorded during a second measurement exceeds the maximum thresholdlevel, and the signal level recorded during a third measurement fallsbelow the minimum threshold level.

FIG. 6 illustrates an example of a method 600 for determining an optimalgain for a booster amplifier. The method 600, or a portion thereof, canalso be combined with the methods of FIG. 5A-5E to prevent or stop abooster amplifier from oscillating, among other things.

The inputs 602 can be received by a control circuit, such as the controlcircuit 314 of FIG. 3. At least some of the inputs 602 can be measuredby the control circuit, stored in memory and accessed when needed,updated regularly by the booster amplifier, and the like.

The inputs 602 correspond to possible external parameters that mayrelate to issues that should be mitigated when setting the gain of thebooster amplifier. Embodiments of the invention may only use some of theinputs and can be configured to accept additional inputs. Examples ofthe parameters that serve as the inputs 602 include, by way of exampleonly:

-   -   Input to the booster amplifier received from a cell phone (or        cell phones) or other device(s);    -   Output from the booster amplifier to a cell phone (or cell        phones) or other device(s);    -   Input to the booster amplifier received from a base station (or        base stations) and/or other wireless networks;    -   Output from the booster amplifier to a base station (or base        stations) and/or other wireless network components;    -   Power/Current supplied to the booster amplifier from the power        source (e.g. battery, power supply, etc.); and/or    -   Indication of a distance between cell phone(s) or other        device(s) and the booster amplifier or its accessories (e.g.        cradle for holding a cell phone, antennas, etc.).

As a result of any of the above inputs 602, and/or in consideration ofrelevant technical requirements, the method determines the control ofthe booster amplifier's circuitry such that optimum gain is obtained inboth directions of amplification, i.e. from the base station(s) to thecell phone(s) or other device(s), and from the cell phone(s) or otherdevice(s) to the base station(s).

FIG. 6 illustrates, in this example, a plurality of subroutines 604 thatcan be performed, for instance, by the control circuit 314 of FIG. 3 orother processor or controller. The subroutines 604 determine potentialgains based on the corresponding input(s). More specifically, thesubroutines 604 a, 604 b, . . . 604 m determine optimum gains for therespective inputs 602 a, 602 b, . . . 602 m or a combination of one ormore of the inputs 602 a, 602 b, . . . 602 m. The subroutines 604 mayinclude subroutines that accept one or more of the inputs 602. As aresult, the number of inputs is not necessarily the same as the numberof the subroutines 604. In some examples, a particular subroutine mayreceive multiple inputs and be able to identify gains for multiplecombinations of the inputs.

For example, the subroutine 604 a may determine potential gain basedupon the input 602 a. Each of the subroutines 604 may be configured tomitigate a particular issue (e.g., power level, oscillation, distancefrom base station, distance from cell phone, power/current from powersource, etc.). When determining a potential gain to mitigate an issue,each subroutine may use more than one of the inputs 602.

In the context of detecting oscillation, one of the inputs may be thestatus determined from comparing the PAPR to a threshold. The status(e.g., normal or oscillation), may be used by the subroutines in eitherconfirming oscillation and/or mitigating the detected oscillation of theamplifier.

The subroutines 604 are not limited to a particular input. For example,the optimum gain to mitigate the distance between the booster amplifierand the base station may use the power/current drawn by the boosteramplifier as well as the input from the base station.

In another example, the subroutines 604 can determine a potential gainaccording to the power level of the signals received from the basestation. When setting the gain in consideration of this issue, thebooster amplifier may i) consider setting the power level at which thesignals are transmitted at a sufficient level to ensure that the signalsreach a target destination; and ii) ensure that the signals transmittedfrom the booster amplifier are transmitted at a power level thatsubstantially eliminates interference.

After the subroutines 604 have identified potential gains to mitigatefor various issues, the control circuit determines 606 the optimum gainGOptimum based on the potential gains (G1-m) produced by the subroutines604. The control circuit may then set 608 the booster amplifier gainequal to the optimum gain GOptimum. The booster amplifier gain may bedifferent for reverse link signals than for forward link signals.

The performance of the booster amplifier is thus compatible with thecellular system and other wireless networks and provides maximumgain/performance to a device of a subscriber using the boosteramplifier. This is done, in one embodiment, by implementing two or moresubroutines. Each subroutine establishes the optimum gain allowable inconsideration of the issues that the subroutines mitigate. In someinstances, the subroutines can mitigate different issues using the sameinput(s). Embodiments generate an optimum or a preferred gain byencompassing several (two or more) subroutines each of which amelioratesa specific problem. The booster amplifier determines the optimum gainallowable for the booster amplifier in consideration of the potentialgains generated by at least some of the subroutines. The boosteramplifier is configured with structure and architecture that is amenableto adding additional subroutines for which the need becomes apparent. Asadditional problems are identified, additional subroutines can beincluded and used in determining the optimal gain for the boosteramplifier.

FIG. 7 illustrates an embodiment of a system and method for setting anoptimum gain. Inputs 702 and 704 can be sensors/detectors that developelectrical output signals that are a function of Forward Link andReverse Link power inputs to a booster amplifier 714, configuredanalogous to the booster amplifiers discussed herein. The Forward Linkpower input 704 is the power that is received from the base station andthe Reverse Link power input 702 is the power received from the cellphone(s) and or other device(s). The booster amplifier 714 may use asingle input 702 for all cell phones or multiple inputs 702. Theseelectrical signals generated by the inputs 702 and 704 are processed bya processor, such as the control circuit 314 of FIG. 3 or othermicro-processor/controller, using three unique subroutines in thisexample.

The first subroutine 706 determines the optimum Gain G1 in considerationof self-oscillation. The first subroutine 706 may be combined with themethod in FIG. 5 to more definitively determine that the amplifier isoscillating before determining the optimum Gain G1. The secondsubroutine 708 determines the optimum Gain G2 considering therequirements of an industry standard, (e.g., TIA-98-F-1 and/or otherstandards). The third subroutine 710 determines the optimum Gain G3 inconsideration of the maximum allowable noise increase in a basestation's receiver or in the base station. Such noise can potentiallyinterfere with the proper performance of base stations, and can bereduced to an acceptable level by controlling the gain of the boosteramplifier 714.

The first subroutine 706 can determine a maximum gain G1 to account foroscillation in the booster amplifier 714 or for oscillation protection.For example, the first subroutine 706 analyzes the inputs (e.g., thecellular signals) in one example to detect the presence of anoscillation in the booster amplifier 714. This subroutine may bepreceded, as previously stated, by the method of FIG. 5 that determinesa status of the booster amplifier 714 based on the PAPR. Where anoscillation is detected or confirmed, the control circuit adjusts thegain G1 in a manner that stops the oscillating condition. The gain G1can be determined by measuring the apparent signal level of the cellularsignal received from the device and/or from the base station. If one orboth of the signals exceed a predetermined signal value, an oscillatorycondition likely exists, and the amplification factor of gain G1 is thenreduced by a predefined amount.

In another embodiment, the booster amplifier 714 is simply shut off whenan oscillation is detected. Alternatively, the value of theamplification factor may be incrementally reduced until the oscillationis eliminated. One embodiment of the invention combines both of theabove aspects, and automatically shuts off the amplification when asevere oscillation is detected, but may alternatively incrementallyreduce the amplification until a less severe oscillation is stopped.

In one example, a method for mitigating oscillation includes sampling asignal multiple times during a predetermined period. A peak to averagepower ratio is determined for the signals based on the samples. Then, apreliminary status of the booster amplifier 714 is determined. Thebooster amplifier 714 is determined to be oscillating when the PAPR isbelow a threshold and determined to be operating normally when the PAPRis above the threshold.

If the status is oscillation, then the method continues by measuring theapparent signal level of the cellular signal received from the deviceand/or from the base station. If one or both of these signals exceeds apredetermined signal value, an oscillatory condition likely exists andthe gain G1 is set accordingly. In other words, the oscillationpreliminarily detected by evaluating the PAPR is verified or confirmedby measuring the signal levels of the signals received from the deviceand/or the base station.

In one example when the status is oscillation, the gain is reducedimmediately when oscillation is detected. The gain in either the reverselink and/or the forward link can be reduced or shut off. While reducingthe gain or when shutting the booster amplifier 714 off, the reverselink power input from the device may still be sampled.

As previously described, embodiments of the booster amplifier 714disclosed here can amplify both forward link and reverse link signals.The amplification factors applied to the forward link and/or reverselink signals can be adjusted when oscillation is detected. The secondsubroutine 708 determines a maximum gain G2. Wireless devices may have abuilt-in power control algorithm that adjusts their power output basedupon the power that they receive from base stations. This built-in powercontrol algorithm is in accordance with the requirements of relevantindustry standards. For example, for CDMA phones, the standard is“Recommended Minimum Performance Standards for cdma2000® Spread SpectrumMobile Stations—Addendum, TIA-98-F-1”, published by theTelecommunications Industry Association. The initial power transmittedby the wireless device to a base station (i.e. before being in closedloop wherein the base station controls the wireless device's transmittedpower) is a function of the power received from the base station. Thiswireless device reverse link (output) power should be maintained withinclose tolerances in order to preclude interfering with the base stationand/or jeopardizing the communicability of the wireless device. Withsome exceptions that will be described, this is expressed,mathematically, by the above mentioned standard as:

Pout=−Pin−K

-   -   Where:    -   Pout is the (reverse link) output power of the wireless device        in dBm;    -   Pin is the (forward link) power that the wireless device        receives from a base station in dBm; and    -   K is a constant depending upon the frequency band and other        factors and is most commonly equal to 73 dB for the 824-894 MHz        band and 76 dB for the 1850-1910 MHz band.

Exceptions in one embodiment:

-   -   Maximum power may never exceed 30 dBm even when the formula        implies a greater value;    -   Whenever the base station commands a wireless device to transmit        Minimum Power, the wireless device's power must be −50 dBm or        less; and    -   Whenever the base station commands a wireless device to transmit        Maximum Power, the wireless device's power must be at least 23        dBm, but not more than 30 dBm.

There may be two inputs to subroutine 708. The first is indicative ofthe reverse link power input received by the booster amplifier 714 froma wireless device, and the second is indicative of the forward linkpower received by the booster amplifier 714 from a base station in oneexample. At any instant, knowing the reverse link power from thewireless device and the forward link power from the base station enablesthe subroutine to determine the gain of the booster amplifier 714 sothat it is compliant with the above formula (e.g., Pout=−Pin−K) andexceptions identified above. The second subroutine 708 determines amaximum value for G2 that is the largest value possible in accordancewith the above formula and special cases (exceptions).

The third subroutine 710 determines a gain for noise floor protection.In general, a booster amplifier transmits thermal noise that isinherently present at its input. The noise power output from any boosteramplifier can be calculated using, by way of example and not limitation,the formula:

N_(out)=FGkTB, where N_(out)=noise power output in watts, F=“noisefactor” of the booster amplifier (this is a measure of the noiseinternally generated by the booster amplifier), G=gain of the boosteramplifier, k=Boltzmann's constant (1.38e-23 watts/Hz-K), T=temperature(degrees Kelvin), and B=bandwidth (Hz).

By knowing the Forward Link power received from the base station, andadditional factors which will be described, the third subroutine is ableto establish a maximum value for gain G3 for the third subroutine 710.

The additional factors may include:

-   -   The equivalent radiated power of the base stations transmitter        (i.e. transmitter power output increased by transmitting antenna        gain and less losses such as those from cables, connectors,        etc.);    -   The maximum allowable increase in noise that is permitted in the        base station receiver, which is more commonly referred to as        “allowable noise floor increase”;    -   The gain of the base station's receiving antenna;    -   The gain of the booster amplifier's antenna;    -   The booster amplifier's gain; and    -   The booster amplifier's noise figure.

The parameters of the base station (e.g. equivalent radiated power,permitted increase in noise, gain of receiving antenna) may be set to betypical values that are generally known, or they may be set to bespecifically required values when necessary, or some may be typicalvalues and others can be set to specifically required values.

At any instant, based upon the received Forward Link power, the thirdsubroutine 710 takes into account at least some of the above mentionedadditional factors and determines the maximum gain G3 such that thenoise power transmitted by the booster amplifier 714 will not cause thenoise floor in the base station's receiver to increase by more than theallowable amount.

The gains G1, G2, and G3 of the subroutines 706, 708, and 710,respectively, are resolved to determine the optimal gain 712 byconsidering all of the gains generated by the subroutines 706, 708, and710 for the booster amplifier 714. The optimal gain can be resolved, forexample, by averaging, by weighted averaging, and the like. The optimalgain may be set to one of the potential gains generated by thesubroutines. Alternatively, the optimal gain may be set to lowestpotential gain (lowest value of G1, G2, G3). In some instances, the gainfrom one subroutine may be given preference or may act as a limit to theoptimal gain.

For example, if the subroutine 706 determines a gain that is associatedwith oscillation, the potential gain determined by the first subroutine706 may limit the optimal gain. In addition, the optimal gain can beupdated repeatedly or continually. As the inputs to the subroutineschange, the optimal gain is likely to change as well. Thus, embodimentsof the invention can dynamically adapt to changes in the inputs that mayimpact the optimal gain of the booster amplifier 714 in either thereverse link and/or forward link direction.

In some embodiments, a microprocessor or control circuitry, withsuitable interface circuitry, may send an electrical signal to a gaincontrol (e.g., a variable attenuator or other VGM) of the boosteramplifier 714 that sets the booster amplifier's 714 gain to be theoptimal value that was determined as described herein.

Before an actual (“closed loop”) connection is made between a basestation and a wireless device (e.g., a cell phone), the wireless deviceis unconnected (“open loop”) and attempts to make a connection bysetting its initial output power based upon the received power from thebase station that it intends to connect with. After making theconnection with a base station, the base station controls the powertransmitted by the wireless device, thereafter making continuouscorrections to the wireless device's power output as may be necessary.However, if the unconnected (“open loop”) transmitted power from awireless device is not within established tolerances, it may not bepossible for the wireless device to connect with the base station.Wireless devices have a built-in power control algorithm that adjuststheir initial output power according to the power that they receive frombase stations. The wireless device's built-in power control algorithm isin accordance with the requirements of relevant industry standards.Embodiments of the booster amplifier 714 disclosed herein ensure thatthe booster amplifier 714 does not interfere with either the closed loopand/or open loop algorithms.

Embodiments of the invention help to reduce the occurrences of thebooster amplifier 714 increasing the Noise Floor of nearby off-channelBase Stations beyond an acceptable amount.

The power transmitted by the booster amplifier 714 thus is configured tobetter meet the requirements of a wireless system, as defined herein oras defined by the wireless system operator, industry standards, orgovernment regulations. The embodiments described herein help reducebase station overloading by an excessively strong signal and helpincrease the ability of the booster amplifier 714 to generate an optimumgain of the base station's forward link signal (received by the cellphone) thereby giving maximum benefit to subscribers while reducing alikelihood of harm to a wireless system.

FIG. 8 illustrates a flow diagram for setting the gain of a boosteramplifier or other device operating in a network environment. FIG. 9illustrates another example of a flow diagram for setting the gain of abooster amplifier or other device. FIG. 10 shows an illustrativeembodiment of a booster amplifier that implements the logic shown inFIGS. 8 and 9. In addition, FIGS. 8, 9 and 10 illustrate an example ofthe subroutines (e.g., the subroutines 706, 708, and/or 710) illustratedin FIG. 7.

The method 800 often begins by sensing 802 inputs. The inputs include,by way of example and not limitation: (i) power input to the boosterreceived from a cell phone (or cell phones) or other device(s) (thoseknowledgeable in the art commonly refer to this as “reverse link” input)and (ii) power input to the booster received from a base station (orbase stations) (those knowledgeable in the art commonly refer to this as“forward link” input).

Knowing the reverse link power from a device and the forward link powerfrom base stations enables determination of the gain of the boosteramplifier that gives maximum benefit to the subscriber while maintainingcompliance with the requirements of wireless systems as explainedherein.

Embodiments also substantially mitigate interference to nearby basestations, which are not in communications with the device. This is oftenreferred to in the technical literature as the “Near/Far” problem. Itoccurs when a device is communicating with a distant (“far”) basestation while, at the same time, the device is physically located veryclose to a “near” base station that the device is not communicatingwith. As a result, the power output of the device) will be maximum inorder to enable communicating with the far base station. But, suchmaximum power will be excessive to the near base station thereby causinginterference, which could be extremely harmful to the near basestation's operation.

Thus, the method 800 often begins by measuring or determining 802 theforward link and reverse link power levels. At block 804, the forwardlink input power is compared to a noise floor threshold level (threshold1). The threshold level is the input that corresponds to a distancewhere noise floor interference is possible. If the forward link inputpower exceeds the noise floor threshold level, then the gain of theamplifier is set 812 to be the gain in a lookup table stored in thebooster amplifier. When the input power does not exceed the noise floorthreshold level, the forward link input power is compared 806 to a poweroverload threshold level to determine if there is a potential problem ofpower overload to nearby base stations. At block 806, a measurement ismade that determines whether or not the forward link input power isgreater than the power overload threshold level (threshold 2). When theforward link input power is less than the power overload thresholdlevel, the gain of the booster amplifier may be set in box 810 to be theMaximum Gain (Gmax). When the forward link input power is greater thanthe power overload threshold level, then the reverse link input power isexamined and compared in box 808 to a second power overload thresholdlevel (threshold 3). If the second power overload threshold level isexceeded, then the booster amplifier's gain is set in box 810 to be theMaximum Gain (Gmax). If, however, the second power overload thresholdlevel is not exceeded, then the booster amplifier's gain is set in box812 to a value determined by the lookup table. After setting the gain ofthe booster amplifier to be either Gmax or to a value from the LookupTable, the method returns to the initial measurement in block 802, andthereafter proceeds as previously described. This repetitive processcontinues as long as the booster amplifier is turned on.

In this way, the booster amplifier can dynamically determine the maximumgain for noise floor protection and/or for power overload protection.

One of skill in the art can appreciate that FIG. 8 illustrates examplesand comparisons, which are performed in blocks 804, 806, and 808, to setthe gain of the booster amplifier. The tests or comparisons in blocks804, 806, and 808, however can be performed in a different order and/orwith different dependencies. These tests or comparisons can also beperformed independently. The gain of the booster amplifier can be set onthe basis of a single comparison or on the basis of multiplecomparisons. In addition, the comparisons used to set a particular gaincan vary over time.

For example, the gain of the booster amplifier could be set based on asingle comparison, any pair of comparisons, or any group of comparisons.In another example, the result of the comparison performed in block 806may be used to trigger the comparison in block 804 and/or block 808.

FIG. 9 illustrates another example of a method 900 for setting the gainof a booster amplifier or other device. In one example, the method 900(similar to other apparatus and methods disclosed herein) may operate toaddress problems such as booster amplifier oscillation, overload issues,and noise floor problems. Often, the gain set or determined in themethod 900 (and other methods disclosed herein) is a maximum gain in thesense that it should not be exceeded based on current conditions. Asdiscussed herein, this gain may be reduced or altered based on otherconditions such as maintaining the linearity of the booster amplifier.

The method 900 begins in box 902 by sampling an input to a boosteramplifier such as the booster amplifier 302 of FIG. 3. The input mayinclude the forward link input power, the reverse link input power, orother inputs or signals as discussed herein.

In box 904, comparisons are performed between the input and thresholds.For example, the forward link input power may be compared to one or morethreshold values or levels. Similarly, the reverse link input power maybe compared to one or more threshold values or levels.

The thresholds may include thresholds that are related to various issuesthat the booster amplifier may encounter. One of the thresholds mayrelate to a noise floor. Another threshold may relate to power overloadprotection. In some instances, the threshold for noise floor or poweroverload protection may be different for different inputs. As describedherein, the comparisons can be performed in any order.

In box 906, outputs are generated from the comparisons performed in box904 (examples of the comparisons are discussed herein and shown by wayof example only in FIG. 8). The gain of the booster amplifier is setbased on the outputs in box 910. When setting the gain, by way ofexample, the booster amplifier may use one or more of the outputs. Theoutputs can be selectively evaluated such that the gain to which thebooster amplifier is set may be based on any combination of the outputs.Each of the various outputs, for example, may be ranked or prioritizedin some examples. The rank or prioritization of the outputs may change,however, based on conditions experienced by the device, boosteramplifier, base station, or the like. In addition, the gain can bedynamically adjusted over time as the outputs of the comparisons change.

In addition, the booster amplifier may also apply automatic gain controlin box 908. Automatic gain control may be applied to the boosteramplifier, for example, to maintain linearity of the booster amplifier.As a result, the gain determined by the outputs of the comparisons maybe further altered by applying automatic gain control. For example, ifthe outputs of the comparisons suggest that the booster amplifier shouldbe set at maximum gain, automatic gain control may reduce the gain, forexample, to maintain linearity. Automatic gain control can be applied inboth the forward link and reverse link directions and the gain may bedifferent in the forward link and the reverse link directions.

In one example, a lookup table, such as illustrated in FIG. 10, may beused when setting the gain or when setting the amplification factors.When the lookup table is used to set the gain, the lookup table may beaccessed, by way of example only, based on whether the various inputsignal levels are greater than or less than the various thresholds,based on one or more of the inputs to the booster amplifier, based onwhat type of issues is being mitigated, or the like or any combinationthereof. For example, when the lookup table is used to set the gain, thelookup table may be accessed according to the forward link input power,the reverse link input power, or the like.

In another example, multiple lookup tables may be present. In this case,the lookup tables may be accessed based on one or more of the inputs(e.g., the forward or reverse link input power) and the type of issuebeing mitigated. As a result, the gain of the booster amplifier can beoptimized using the lookup tables. FIG. 10 illustrates an example of abi-directional booster amplifier 1020. In FIG. 10, a sample relative tothe power level of the forward link signal from the Base Station isdetected to determine whether the signal is above or below eitherThreshold 1 or Threshold 2. The sample 1002 is provided to a detector1006 and a detector 1008. The detector 1006 can determine whether thesample 1002 exceeds the threshold 1 and the detector 1008 can determinewhether the sample 1002 exceeds the threshold 2. Similarly, a sample1004 relative to the power level of the reverse link signal from asubscriber's device (e.g., cell phone, PDA, etc.) is detected todetermine whether the signal is above or below Threshold 3 using adetector 1010. The samples may be provided as a voltage and thecomparisons of the samples 1002 and 1004 to the relevant thresholds canbe achieved using a voltage comparison circuit (which may be included inthe processor 1014). The samples can be converted to digital valuesbefore comparison to the relevant threshold values.

The outputs from the three threshold detectors 1006, 1008, and 1010 areprovided to the processor 1014. The processor 1014 may be amicroprocessor, or a simple transistor or other logic circuit. Theprocessor 1014 is also connected to a lookup table 1012 that could be anintegral part of the processor 1014 or may be located in memory that isexternal to the processor 1014. The processor 1014 examines the outputsof the detectors 1006, 1008, and 1010 and also examines the Lookup Table1012 (as needed) in order to determine the required gain of thebi-directional booster amplifier 1020 as described with reference toFIGS. 8 and 9. After the required or optimal gain is determined, theprocessor 1014 originates a signal that feeds the gain control interface1018. The gain control interface 1018 gives the correct drive (orsignal) to the device(s) that actually adjust(s) the gain of thebi-directional booster amplifier 1020. As previously stated, the gaincontrol interface 1018 may also apply automatic gain control to thebi-directional booster amplifier 1020, which may change or reduce theoptimal gain, for various reasons, such as to maintain linearity of thebi-directional booster amplifier 1020.

There are several types of devices that could enable adjustable gain.Some examples are: pin-diode attenuators and active gain devices whosegain depends upon a DC control voltage, etc. The gain of thebi-directional booster amplifier 1020 may or may not be equal in forwardlink and reverse link directions depending upon the characteristics ofthe signals being amplified by the bi-directional booster amplifier1020. The threshold detectors 1006, 1008, and 1010, the processor 1014,lookup table 1012, and gain control interface 1018 could be included inone hardware device (e.g. a PIC).

The lookup table(s) may include values that are determined according tocharacteristics of the bi-directional booster amplifier 1020, basestations, and device(s). For instance, the maximum gain of thebi-directional booster amplifier 1020 and the noise figure of thebi-directional booster amplifier 1020 may influence the values in thelookup table. The allowable increase in the base station noise floor,and equivalent isotropic radiated power of the base station, the forwardlink power received at the antenna input of the bi-directional boosteramplifier 1020, the maximum cell phone radiated power, the gain of thebase station receive antenna, the path loss between the bi-directionalbooster amplifier 1020 and the base station, and the path loss betweenthe bi-directional booster amplifier 1020 and device(s), are additionalexamples of values that may influence the parameters set in the lookuptable.

The following paragraphs assume the following values:

-   -   Maximum Gain of bi-directional booster amplifier 1020=38 dB;    -   Noise figure of bi-directional booster amplifier 1020=6 dB;    -   Allowable increase in base station noise floor=0.06 dB;    -   Base Station Output Power=30 dBm;    -   Forward Link Power received at bi-directional booster amplifier        1020 outside antenna input=−28.9 dBm;    -   Maximum Cell Phone Radiated Power=23 dBm;    -   Path Loss between bi-directional booster amplifier 1020 and base        station=77.6 dB; and    -   Path Loss between bi-directional booster amplifier 1020 and cell        phone=17 dB

In this example, the above parameter values may be for thebi-directional booster amplifier 1020 and typical base stationcharacteristics. One of skill in the art can appreciate thedetermination of other values based on another booster amplifier and/orbase station characteristics and/or path losses. In addition, changes tothese values may require changing the lookup tables used to set the gainin the bi-directional booster amplifier 1020.

As previously stated, some of the values may be determined according tothe characteristics of the bi-directional booster amplifier 1020. Forexample, to protect the base station noise floor when the forward linkinput power is equal to −27 dBm, the maximum allowable reverse link gainplus noise figure of the bi-directional booster amplifier 1020 is 38 dB.The bi-directional booster amplifier 1020 should lower its gain to thislevel even if this results in shutting the bi-directional boosteramplifier 1020 off. This is an example of the gain of the bi-directionalbooster amplifier 1020 for the first threshold, for example, at 804 inFIG. 8.

For the second threshold and to protect against base station overload,for example at 806 in FIG. 8, when the forward link input power is −38dBm the maximum allowable reverse link gain of the bi-directionalbooster amplifier 1020 is 21 dB.

For the third threshold and to protect from base station overload, forexample at 808 in FIG. 8, when the reverse link input power is +8 dBmthe maximum allowable reverse link gain of the bi-directional boosteramplifier 1020 is 22 dB. The level of the reverse and forward link inputpowers allows the bi-directional booster amplifier 1020 to determinewhether the device (e.g., cell phone) is communicating with a near orfar base station in order to optimize gain.

In one example, a gain in a bi-directional booster amplifier 1020 is setby initially measuring a forward link input power and/or a reverse linkinput power. The forward link input power is compared to a noise floorthreshold level. A gain of the bi-directional booster amplifier 1020 isset to a value in a lookup table when the forward link input powerexceeds the noise floor threshold level.

If necessary, the forward link input power is compared to a first poweroverload protection threshold level when the forward link input powerdoes not exceed the noise floor threshold level and the gain is set to amaximum gain when the forward link input power does not exceed the firstpower overload protection threshold level.

If necessary, the reverse link input power is compared to a second poweroverload protection threshold level when the forward link input powerexceeds the first power overload protection threshold level. The gain isset to the maximum gain when the reverse link input power exceeds thesecond power overload protection threshold level. Alternatively, thegain is set according to a value in the lookup table when the reverselink input power does not exceed the second power overload protectionthreshold level.

As described previously, with respect to FIGS. 4 and 5A, a boosteramplifier may be configured to detect oscillations based on a signalpower ratio within the booster amplifier. As described, the boosteramplifier may be configured to sample the power of a signal within thebooster amplifier one or more times. The booster amplifier may befurther configured to analyze the power samples to determine a powerratio of the signal within the booster amplifier. One such power ratiomay be a PAPR ratio. Based on the comparison of the power ratio to athreshold value, which may be computed based on the characteristics ofthe wireless network in which the booster amplifier is operating, thebooster amplifier may be able to determine if an oscillation isoccurring. In some embodiments, a power ratio of a signal determined bythe booster amplifier may be a difference between powers levels of thepower samples. For example, the power ratio of a signal may be adifference between a power sample with a highest power and a powersample with a lowest power or an average power of the power samples.

As noted, however, in some circumstances, comparing a determined powerratio to a threshold value for determining oscillations (referred tohereafter as power-ratio oscillation detection) may provide falseindications (also referred to as false positives) that the boosteramplifier is oscillating. In particular, in networks where signalingschemes do not provide a comparatively large PAPR ratio, a boosteramplifier may falsely detect an oscillation using the power-ratiooscillation detection method, described above. While power-ratiooscillation detection may result in false positives, power-ratiooscillation detection does not have the booster amplifier adjust anamplification factor applied to a signal in the booster amplifier. Notadjusting an amplification factor applied to a signal in the boosteramplifier may reduce spurious noise and other unwanted effects that mayresult from adjusting an amplification factor applied to a signal.

In some embodiments, a booster amplifier may be configured to perform anadditional oscillation detection method to verify that an oscillation isin fact occurring after power-ratio oscillation detection indicates thatoscillation is occurring. In these and other embodiments, the boosteramplifier may be configured to reduce the time and computationresources, among other things, in performing an additional oscillationdetection method by using the power samples previously collected for thepower-ratio oscillation detection. For example, FIG. 5D illustrates amethod of detecting oscillations that may not result in false positivedetections of oscillation, which may be referred to herein asamplification-adjust oscillation detection.

FIG. 5D illustrates that a first power measurement of a signal is takenwhile a first amplification factor is applied to the signal and, afterapplying a second application factor to the signal, taking a secondpower measurement of the signal. After the power-ratio oscillationdetection method detects an oscillation, the amplification-adjustoscillation detection method may use the power samples collected duringthe power-ratio oscillation detection method in place of measuring thepower of a signal while a first amplification factor is applied.

In these and other embodiments, after the power-ratio oscillationdetection method determines that the booster amplifier is oscillating,the amplification-adjust oscillation detection method may adjust theamplification factor being applied to a signal and measure the power ofthe signal at the adjusted amplification factor. Theamplification-adjust oscillation detection method may then compare apower of the signal determined by the power-ratio oscillation detectionmethod with the power of the signal at the adjusted amplification factorto verify that the booster amplifier is oscillating.

When the power of the signal at the adjusted amplification factor issignificantly less than the power of the signal determined by thepower-ratio oscillation detection method, the oscillation of the boosteramplifier may be verified. In some embodiments, oscillations of thebooster amplifier being indicated by the power of the signal at theadjusted amplification factor being significantly less than the power ofthe signal determined by the power-ratio oscillation detection methodmay be true when the power of the signal is measured before the adjustedamplification factor is applied to the signal. When the power of thesignal is measured after the adjusted amplification factor is applied tothe signal, a difference between the power of the signal at the adjustedamplification factor to the power of the signal determined by thepower-ratio oscillation detection method that is not significantly lessmay indicate oscillation of the booster amplifier. Thus, differentbooster amplifiers may rely on different differences between the powerof the signal at the adjusted amplification factor and the power of thesignal determined by the power-ratio oscillation detection method todetermine oscillations. However, these different differences between thepower of the signal used to determine oscillations may be related to thedifferent locations in the booster amplifier where the power of thesignal is measured and not to the booster amplifier performing differentmethods for determining oscillations of the booster amplifier.

In some embodiments, when a difference between the power of the signalat the adjusted amplification factor and the power of the signaldetermined by the power-ratio oscillation detection method is greaterthan the adjustment made to the amplification factor applied to thesignal, the oscillation of the booster amplifier may be verified. Whenthe oscillation of the booster amplifier is verified, steps may be takento reduce or eliminate the oscillation of the booster amplifier asdescribed herein.

Note that in some embodiments, an amount that the amplification-adjustoscillation detection method may adjust an amplification factor beingapplied to a signal and measure the power of the signal at the adjustedamplification factor may not be sufficient to stop oscillation of abooster amplifier. For example, a booster amplifier may be applying anamplification factor of 70 dB to a signal. Oscillations may occur in thebooster amplifier when the booster amplifier applies an amplification of30 dB or greater to a signal. As a result, if the amplification-adjustoscillation detection method adjust the amplification factor by loweringthe amplification factor by less than 40 dB, the oscillation maycontinue. As a result, the power of the signal at the adjustedamplification factor and the power of the signal determined by thepower-ratio oscillation detection method may not be significantlydifferent as to indicate an oscillation as when the adjustedamplification factor is lowered below the 30 dB threshold foroscillation.

Thus, the amplification-adjust oscillation detection method may render afalse negative by indicating that the booster amplifier is notoscillating when the booster amplifier is oscillating. Note that theamplification-adjust oscillation detection method may not render falsenegatives if the adjusted amplification factor is less than the smallestadjusted amplification factor that may result in external oscillations.In some embodiments, the smallest adjusted amplification factor that mayresult in external oscillations may be approximately equal to thesmallest path loss between antennas attached to the booster amplifier.In some embodiments, the smallest path loss may be approximately 5 dB orless.

However, in some embodiments, it may be advantageous to adjust theamplification factor in the amplification-adjust oscillation detectionmethod so that the adjusted amplification factor is greater than thesmallest path loss between antennas attached to the booster amplifier orapproximately 5 dB to reduce the amount of adjustment of theamplification factor in the amplification-adjust oscillation detectionmethod. Reducing the amount of adjustment of the amplification factormay reduce noise created by the booster amplifier. For example, theamplification factor may be adjusted down 5, 10, 15, or 20 dB, duringthe amplification-adjust oscillation detection method.

Limiting the adjustment to the amplification factor during theamplification-adjust oscillation detection method may generate a falsenegative as noted. To compensate for the possibility of false negatives,the power-ratio oscillation detection method may be performed a secondtime. In some embodiments, the second iteration of the power-ratiooscillation detection method may be performed after theamplification-adjust oscillation detection method is performed where theadjusted amplification factor is less than or equal to the smallest pathloss between antennas attached to the booster amplifier. Alternately oradditionally, the second iteration of the power-ratio oscillationdetection method may be performed after the amplification adjustoscillation detection method is performed, where the adjustedamplification factor is less than or equal to the smallest path lossbetween antennas attached to the booster amplifier, when theamplification adjust oscillation detection method is inconclusive. Theamplification adjust oscillation detection method may be inconclusivewhen a difference between the power of the signal at the adjustedamplification factor and the power of the signal determined by thepower-ratio oscillation detection method is not approximately equal tothe amount of the adjustment of the amplification factor. In someembodiments, when the amplification adjust oscillation detection methodconclusively indicates an oscillation, a second iteration of thepower-ratio oscillation detection method may not be performed. Theamplification adjust oscillation detection method may be conclusive whena difference between the power of the signal at the adjustedamplification factor and the power of the signal determined by thepower-ratio oscillation detection method is approximately equal to theamount of the adjustment of the amplification factor.

The second iteration of the power-ratio oscillation detection method maysample the signal to obtain new power samples of the signal to performthe power-ratio oscillation detection method. In these and otherembodiments, the second iteration of the power-ratio oscillationdetection method may sample the signal more than the signal is sampledduring the first iteration of the power-ratio oscillation detectionmethod. For example, in some embodiments, the signal may be sampled 2 to10 times more than during the first iteration. For example, during thefirst iteration, the signal may be sampled 200 times and during thesecond iteration the signal may be sampled 1000 times. In these andother embodiments, the second iteration of the power-ratio oscillationdetection method may also render a false positive. However, a falsepositive is more acceptable than a false negative, as rendered by theamplification-adjust oscillation detection method, because a falsepositive does not allow for the booster amplifier to continueoscillating and cause interference with other wireless communications.Furthermore, sampling the signal multiple times more during the seconditeration than the first iteration of the power-ratio oscillationdetection method may result in less false positives. When the seconditeration of the power-ratio oscillation detection method indicates thatthe booster amplifier is oscillating, the booster amplifier may takeappropriate action as described herein.

FIG. 11 is a flow chart of an example method 1100 of managingoscillations of a booster amplifier in a wireless network, arranged inaccordance with at least some embodiments described herein. The method1100 may be implemented, in some embodiments, by a booster amplifier,such as the booster amplifier 302 or 402 of FIGS. 3 and 4, respectively.For instance, the control circuit 314 of the booster amplifier 302 ofFIG. 3 may be configured to execute computer instructions to performoperations for managing oscillations of the booster amplifier 302 asrepresented by one or more of blocks 1102, 1104, 1106, 1108, 1110, and1112 of the method 1100. Although illustrated as discrete blocks,various blocks may be divided into additional blocks, combined intofewer blocks, or eliminated, depending on the desired implementation.

The method 1100 may begin at block 1102, where power of a wirelesssignal in a booster amplifier within a wireless network may be sampledmultiple times over a period to obtain multiple power samples of thewireless signal. In some embodiments, the method 1100 may includereceiving the wireless signal at the booster amplifier.

In some embodiments, the power of the wireless signal may be sampled atan input to an amplifier chain within the booster amplifier, an outputto the amplifier chain, or within the amplifier chain. In these andother embodiments, the amplifier chain may include at least oneamplifier and may be configured to apply the amplification factor to thewireless signal.

In block 1104, a power ratio of the wireless signal may be determinedusing the multiple power samples of the wireless signal. For example,the power ratio of the wireless signal may be a peak to average powerratio (PAPR) or a peak to minimum power ratio. In some embodiments, thepower ratio of the wireless signal may be based on one or more of a peakpower of the wireless signal during the period, a minimum power of thewireless signal during the period, a medium power of the wireless signalduring the period, a root mean square of the wireless signal during theperiod, and a mean power of the wireless signal during the period, amongothers.

In block 1106, the power ratio of the wireless signal may be compared toa threshold power ratio that is based on a configuration of the wirelessnetwork. For example, if the wireless network is a CDMA network, thethreshold power ratio may be based on a CDMA PAPR. In particular, thethreshold power ratio may be determined based on signaling power ratiosof wireless signal being communicated in the wireless network.

In block 1108, it may be determined when the comparison of the powerratio of the wireless signal to the threshold power ratio indicatesoscillation of the booster amplifier. In some embodiments, the powerratio of the wireless signal being below the threshold power ratio mayindicate oscillation of the booster amplifier. When the comparison ofthe power ratio of the wireless signal to the threshold power ratioindicates oscillation, block 1108 may be followed by blocks 1110 and1112. When the comparison of the power ratio of the wireless signal tothe threshold power ratio does not indicate oscillation, the method 1100may end.

In block 1110, the wireless signal in the booster amplifier may besampled to obtain a second power sample after reducing an amplificationfactor applied by the booster amplifier to the wireless signal. In someembodiments, the amplification factor may be greater than one afterbeing reduced.

In block 1112, the second power sample may be compared to at least oneof the multiple power samples. In some embodiments, the second powersample may be compared to an average of one or more of the multiplepower samples, a highest of the multiple power samples, the lowest ofthe multiple power samples, or some other subset of the multiple powersamples. In some embodiments, a third power sample may be obtained. Inthese and other embodiments, the second power sample may be compared tothe third power sample.

In some embodiments, the booster amplifier may be verified to beoscillating when the second power sample is significantly less than oneof the multiple power samples. In some embodiments, the boosteramplifier may be verified to be oscillating when a difference betweenthe second power sample and the one of the multiple power samples islarger than the reduction of the amplification factor applied by thebooster amplifier to the wireless signal. In some embodiments, where thereduction in the amplification factor does not approach the smallestpath loss between antennas attached to the booster amplifier or 5 dB orless, for example when the reduction in the amplification factor isapproximately 3 to 30 dB, the second power sample may not besignificantly less than the one of the multiple power samples, but thebooster amplifier may be oscillating. Whether the amplification factorapproaches or is smaller than the smallest path loss between antennasattached to the booster amplifier or 5 dB or less may vary depending ofthe booster amplifier and the configuration of antennas attached to thebooster amplifier.

In these and other embodiments, comparing the second power sample to theone of the multiple power samples may not verify oscillation of thebooster amplifier. To verify the oscillation of the booster amplifier,the method 500 may include resampling power of the wireless signal inthe booster amplifier a second multiple of times over a second period toobtain a second multiple of power samples of the wireless signal anddetermining a second power ratio of the wireless signal using the secondmultiple of power samples of the wireless signal. The method 500 mayfurther include comparing the second power ratio of the wireless signalto the threshold power ratio. In these and other embodiments, thecomparing the second power ratio to the threshold power ratio may verifyoscillation of the booster amplifier.

One skilled in the art will appreciate that, for this and otherprocesses and methods disclosed herein, the functions performed in theprocesses and methods may be implemented in differing order.Furthermore, the outlined steps and operations are only provided asexamples, and some of the steps and operations may be optional, combinedinto fewer steps and operations, or expanded into additional steps andoperations without detracting from the essence of the disclosedembodiments.

For instance, the method 1100 may further include reducing theamplification factor applied by the booster amplifier to the wirelesssignal to be less than one when the booster amplifier is verified to beoscillating.

In some embodiments, when the oscillation of the booster amplifier isnot verified, the method 1100 may further include increasing theamplification factor applied by the booster amplifier to the wirelesssignal. In some embodiments, when it is determined that the detectedoscillation is not an oscillation but a false positive, the method 1100may include increasing the amplification factor an amount that theamplification factor was reduced.

By detecting oscillations and reducing an amplification factor to stopcurrent oscillations or to prevent oscillations, noise generated by abooster amplifier may be reduced. Reducing noise generated by a boosteramplifier may help to reduce the noise floor of the network system inwhich the booster amplifier is operating. Reducing the noise floor of anetwork system or maintaining a low noise floor in a network system maybe advantageous to a network system.

Noise generated by a booster amplifier may be further reduced byapplying an amplification factor to a signal that is not significantlyclose to an amplification factor that causes oscillation of the boosteramplifier. An amplification factor that causes oscillation of a boosteramplifier may be referred to herein as an oscillation amplificationfactor. An amplification factor applied by a booster amplifier may bereferred to herein as an applied amplification factor.

When an applied amplification factor of a booster amplifier approachesan oscillation amplification factor of the booster amplifier, the noiseoutput by the booster amplifier may increase. For example, when anapplied amplification factor is near to an oscillation amplificationfactor so that a difference between the amplification factors results inone dB of amplification, the difference in noise output by the boosteramplifier may be twenty to thirty dB. In comparison, when a differencebetween an applied amplification factor and an oscillation amplificationfactor results in three dB of amplification, the difference in noiseoutput by the booster amplifier may be six to eight decibels. Thus, itmay be advantageous to maintain an amplification factor margin betweenan applied amplification factor and an oscillation amplification factorof a booster amplifier.

An amount of an amplification factor margin selected for a boosteramplifier may vary based on the booster amplifier, a network in whichthe booster amplifier may operate, a desired noise floor, among otherfactors. In some embodiments, the amplification factor margin may resultin an amplification margin of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. 12, or 15decibels.

A booster amplifier may be configured to establish and maintain at leastan amplification factor margin between the booster amplifier's appliedamplification factor and the booster amplifiers' oscillationamplification factor. Note that under certain circumstances, a boosteramplifiers' oscillation amplification factor may vary. A boosteramplifiers' oscillation amplification factor may vary based on anenvironment external to the booster amplifier and changing conditionswithin the external environment. In particular, a booster amplifiers'oscillation amplification factor may vary based on changing path lossconditions within the external environment. As a result, to maintain anamplification factor margin between a booster amplifier's appliedamplification factor and the booster amplifiers' oscillationamplification factor, the booster amplifier may periodically orcontinually adjust the booster amplifiers' applied amplification factor.

As an example, in some embodiments, a booster amplifier may detectchanges in the booster amplifiers' oscillation amplification factorevery three seconds. In some embodiments, the time between checking forchanges in a booster amplifiers' oscillation amplification factor may bemore or less than every three seconds. In some embodiments, thefrequency of detecting changes in a booster amplifiers' oscillationamplification factor may depend on factors such as the use of thebooster amplifier (e.g., within a moving vehicle versus a stationarybuilding) and the sensitivity of the network, in which the boosteramplifier operates, to noise. The use of the booster amplifier may besignificant because it may affect how often path loss conditionssurrounding the booster amplifier are changing and thereby affect thebooster amplifiers' oscillation amplification factor.

An example booster amplifier configured to detect an oscillationamplification factor and to adjust an applied amplification factor basedon an amplification factor margin may be described with respect to FIG.4 and the booster amplifier 400.

For example, in some embodiments, the booster amplifier 400 may beconfigured to establish and to maintain at least an amplification factormargin between the booster amplifier's 400 applied amplification factorand the booster amplifiers' 400 oscillation amplification factor.

The booster amplifier 400 may have a particular amplification factormargin that may be used by the booster amplifier 400. In someembodiments, the amplification factor margin may be set. In someembodiments, the amplification factor margin may vary based on a networkin which the booster amplifier 400 is operating. For example, somenetworks may tolerate more noise than other networks and thereby mayallow for smaller amplification factor margins that may result ingreater noise being generated by the booster amplifier 400. In someembodiments, the amplification factor margin may also be based on adistance between the booster amplifier 400 and a base station, wheresignals from the base station are amplified by the booster amplifier400. In these and other embodiments, when the booster amplifier 400 isfurther from the base station, the amplification factor margin may besmaller than if the booster amplifier 400 is closer to the base station.Thus, in some embodiments, the amplification factor margin may varyduring operation of the booster amplifier 400 based on one or morefactors associated with the wireless network in which the boosteramplifier 400 is operating. For example, the booster amplifier 400 maycalculate an approximate distance between the booster amplifier 400 andthe base station as described previously and set the amplificationfactor margin based on the calculated distance and/or other factors,such as the type of network in which the booster amplifier 400 isoperating.

The microcontroller 414 may be configured to perform operations based oninstructions within a computer readable medium to establish and/or tomaintain an amplification factor margin between the booster amplifier's400 applied amplification factor and the booster amplifiers' 400oscillation amplification factor.

After the booster amplifier 400 commences operations and is applying anapplied amplification factor to a signal, the microcontroller 414 may beconfigured to establish an amplification factor margin. To establish theamplification factor margin, the microcontroller 414 may direct theamplification control circuit 412 to increase the amplification factorbeing applied by the amplifier chain 404 to the signal by theamplification factor margin. With the increased amplification factorbeing applied to the signal, the oscillation detector 410 may detect ifan oscillation is occurring at the increased amplification factor. Theoscillation detector 410 may apply any one of the multiple methodsdescribed herein or any combination of the methods described herein todetect oscillations in the booster amplifier 400. After detectingoscillations, in some embodiments, the booster amplifier 400 may stopapplying the amplification factor margin to the signal so that just theapplied amplification factor is being applied to a signal within thebooster amplifier 400.

When no oscillations are detected, the microcontroller 414 may increasethe applied amplification factor and direct the amplification controlcircuit 412 to apply the increased applied amplification factor to thesignal by way of the amplifier chain 404. The microcontroller 414 mayincrease the applied amplification factor by an amount smaller than,equal to, or larger than the amplification factor margin.

The microcontroller 414 may then repeat the process by directing theamplification control circuit 412 to increase the amplification factorby the amplification factor margin and by directing the oscillationdetector 410 to detect if oscillations are occurring, until anoscillation in the booster amplifier 400 occurs. Once an oscillationoccurs, the microcontroller 414 may change the applied amplificationfactor to an applied amplification margin used previously or to someother value, or maintain the applied amplification factor.

As an example, an initial applied amplification factor may result in 40dB of amplification and an amplification factor margin of 4 dB. In thisexample, the booster amplifier 400's oscillation amplification factormay be related to 47 dB of amplification. Further, in this example, themicrocontroller 414 may increase the initial applied amplificationfactor so that the amplification applied by the booster amplifier 400increases by 1 dB. Thus, the amplification applied by the appliedamplification factor would increase from 40 dB to 41 dB to 42 dB andfinally to 43 dB. At 43 dB, when the amplification factor margin (4 dB)is added to the applied amplification factor, oscillations may occurbecause the applied amplification factor plus the amplification factormargin may approximately equal the oscillation amplification factor (47dB). To maintain the amplification factor margin between the appliedamplification factor and the oscillation amplification factor, theapplied amplification factor may be established so that 43 dB or less ofamplification is applied to a signal.

When oscillations are detected after the booster amplifier commencesoperations and the increased amplification factor (e.g the appliedamplification factor plus the amplification factor margin) is beingapplied to the signal, the microcontroller 414 may stop applying theamplification factor margin and decrease the applied amplificationfactor and direct the amplification control circuit 412 to apply thedecreased applied amplification factor. The microcontroller 414 maydecrease the applied amplification factor by an amount smaller than,equal to, or larger than the amplification factor margin.

The microcontroller 414 may then repeat the process by directing theamplification control circuit 412 to increase the decreased appliedamplification factor by the amplification factor margin and checking foroscillations until oscillations in the booster amplifier 400 stopoccurring. Once oscillations stop occurring when a decreased appliedamplification factor and the amplification factor margin are applied,the microcontroller 414 may establish the decreased appliedamplification factor as the applied amplification factor.

In some embodiments, when oscillations are detected, the microcontroller414 may decrease the applied amplification factor a significant amountand then apply the process of increasing the applied amplificationfactor as discussed above until an applied amplification factor isdetermined with the particular amplification factor margin.

After establishing the amplification factor margin, the microcontroller414 may be configured to maintain the amplification factor marginbetween the applied amplification factor and the oscillatingamplification factor by periodically increasing the appliedamplification factor by the amplification factor margin and respondingaccordingly when an oscillation is detected. In some embodiments, whenoscillations are not detected after a certain period, themicrocontroller 414 may increase the applied amplification factor todetermine if the oscillation amplification factor has been increased toallow an increase in the applied amplification factor while stillmaintaining the amplification factor margin.

In some embodiments, after the booster amplifier 400 commencesoperations and is applying an applied amplification factor to a signal,the microcontroller 414 may be configured to establish an amplificationfactor margin by checking for oscillations. When oscillations are notoccurring at the applied amplification factor, the booster amplifier 400may reduce the applied amplification factor by the amplification factormargin and thereby establish the amplification factor margin. Whenoscillations are occurring at the applied amplification factor, thebooster amplifier 400 may reduce the applied amplification factor. Thebooster amplifier 400 may reduce the applied amplification factor by aparticular amount that is less than, greater than, or equal to theamplification factor margin. After reducing the applied amplificationfactor, the booster amplifier 400 may again attempt to establish theamplification factor margin by performing any one of the multiplemethods of establishing an amplification factor margin discussed herein.

In some embodiments, the applied amplification factor determined basedon the amplification factor margin may not be an amplification factorthat is actually applied by the booster amplifier 400 to a signal. Inthese and other embodiments, the applied amplification factor may be ahighest amplification factor that may be considered by the boosteramplifier 400 for amplifying a signal. For example, the boosteramplifier 400 may apply one or more other algorithms as discussed hereinto determine an amplification factor to apply to a signal. The appliedamplification factor may limit the amplification factor that may beselected by the booster amplifier 400 based on these other algorithms toprevent excess noise from being introduced into a network by the boosteramplifier 400. In these and other embodiments, the booster amplifier 400may select an applied amplification factor differently than explainedhere, but may still periodically and/or continually check that theamplification factor margin is being maintained as described herein.

Note that in some embodiments, the process of maintaining anamplification factor margin may occur less periodically than otherprocesses performed by the booster amplifier 400. For example, thebooster amplifier 400 may perform oscillation detection as describedherein with respect to FIGS. 5A-5E once every thirty milliseconds. Incontrast, maintaining or establishing an amplification factor margin mayoccur once every three seconds. In some embodiments, maintaining orestablishing an amplification factor margin may be performed inconjunction with the oscillation detection described herein with respectto FIGS. 5A-5E. For example, every hundredth oscillation detection maybe performed at a reduced or increased applied amplification factor usedto maintain or establish an amplification factor margin.

As an example, an initial applied amplification factor may result in 40dB of amplification and an amplification factor margin, when applied,may result in 4 dB of additional amplification. In this example, thebooster amplifier 400's oscillation amplification factor may be relatedto 45 dB of amplification. Further, in this example, the microcontroller414 may increase the initial applied amplification factor (40 dB) by theamplification factor margin (4 dB) and check for oscillations. When nooscillations occur, the microcontroller may stop applying theamplification factor margin and may increase the amplified amplificationfactor so that the amplification applied by the booster amplifier 400increases by 1 dB to 41 dB. Note that in some embodiments, themicrocontroller 410 may perform the stopping the application of theamplification factor margin and the increasing the amplifiedamplification factor in a single step. For example, the microcontroller410 may just decrease the amplification applied to a signal to 41 dBinstead of decreasing to 40 dB and then increasing to 41 dB.

After a time period, such as two seconds, the microcontroller mayincrease the applied amplification factor (41 dB) by the amplificationfactor margin (4 dB) and check for oscillations. At 41 dB, when theamplification factor margin (4 dB) is added to the applied amplificationfactor, oscillations may occur because the applied amplification factorplus the amplification factor margin may approximately equal theoscillation amplification factor (45 dB). To maintain the amplificationfactor margin between the applied amplification factor and theoscillation amplification factor, the applied amplification factor maybe established so that less than 41 dB of amplification is applied to asignal.

Note that the amplification factor margin discussed herein, in someembodiments, may be a desired amplification factor margin for thebooster amplifier. In these and other embodiments, the actualamplification factor margin between the applied amplification factor andthe oscillation amplification factor may vary due to various reasons,such as changing environmental conditions.

Modifications, additions, or omissions may be made to the boosteramplifier 400 without departing from the scope of the presentdisclosure. For example, the oscillation detector 410 and themicrocontroller 414 may be combined in a single unit. Alternately oradditionally, the microcontroller 414 may be configured to perform otherprocess for managing oscillations amplification factors than thosedescribed.

FIG. 12 is a flow chart of an example method 1200 of managing anoscillation amplification factor margin of a booster amplifier in awireless network, arranged in accordance with at least some embodimentsdescribed herein. The method 1200 may be implemented, in someembodiments, by a booster amplifier, such as the booster amplifier 400of FIG. 4. For instance, the microcontroller 414 of the boosteramplifier 400 of FIG. 4 may be configured to execute computerinstructions to perform operations for detecting and managing anoscillation amplification factor margin of the booster amplifier 400 asrepresented by one or more of blocks 1202, 1204, and 1206 of the method1200. Although illustrated as discrete blocks, various blocks may bedivided into additional blocks, combined into fewer blocks, oreliminated, depending on the desired implementation.

The method 1200 may begin at block 1202, where a wireless signal withina wireless network received by a booster amplifier may be amplified byan amplification factor. In particular, the amplification factor appliedby the booster amplifier may be a first applied amplification factor. Insome embodiments, the first applied amplification factor may not causeoscillation in the booster amplifier.

In block 1204, it may be determined if the booster amplifier isoscillating by checking for oscillations of the booster amplifier. Inblock 1206, it may be determined if oscillations of the boosteramplifier are occurring. When oscillations are occurring in the boosteramplifier, block 1206 may be followed by block 1210. When oscillationsare not occurring in the booster amplifier, block 1206 may be followedby block 1208.

In block 1208, the first applied amplification factor may be reduced byan amplification factor oscillation margin. In some embodiments, theamplification factor oscillation margin may result in at least anamplification oscillation margin of three decibels.

In block 1210, the first applied amplification factor may be reduced bya particular amount. In some embodiments, the particular amount may begreater than, less than, or equal to the amplification factoroscillation margin.

One skilled in the art will appreciate that, for this and otherprocesses and methods disclosed herein, the functions performed in theprocesses and methods may be implemented in differing order.Furthermore, the outlined steps and operations are only provided asexamples, and some of the steps and operations may be optional, combinedinto fewer steps and operations, or expanded into additional steps andoperations without detracting from the essence of the disclosedembodiments.

For instance, the method 1200 may further include setting theamplification factor to the first applied amplification factor tomaintain the amplification factor oscillation margin. In someembodiments, the method 1200 may further include maintaining at leastthe amplification factor oscillation margin between the amplificationfactor and an oscillation amplification factor that causes oscillationsin the booster amplifier.

In some embodiments, when the particular amount is greater than theamplification factor oscillation margin, the method 1200 may furtherinclude checking for oscillation of the booster amplifier when theamplification factor is at a second applied amplification factor lessthan the first applied amplification factor. When the booster amplifieris not oscillating, the method 1200 may further include increasing theamplification factor by the amplification factor oscillation margin andrechecking for oscillation of the booster amplifier after the increasingthe amplification factor. In some embodiments, the second appliedamplification factor may be greater than the first applied amplificationfactor reduced by the particular amount.

In some embodiments, checking for oscillation of the booster amplifiermay further include sampling power of the wireless signal in the boosteramplifier multiple times over a period to obtain multiple power samplesof the wireless signal and determining a power ratio of the wirelesssignal using the multiple power samples of the wireless signal. Checkingfor oscillation of the booster amplifier may further include comparingthe power ratio of the wireless signal to a threshold power ratio thatis based on a configuration of the wireless network. Other methods ofdetecting oscillations of the booster amplifier as disclosed herein mayalso be used.

FIG. 13 is a flow chart of another example method 1300 of managing anoscillation amplification factor margin of a booster amplifier in awireless network, arranged in accordance with at least some embodimentsdescribed herein. The method 1300 may be implemented, in someembodiments, by a booster amplifier, such as the booster amplifier 400of FIG. 4. For instance, the microcontroller 414 of the boosteramplifier 400 of FIG. 4 may be configured to execute computerinstructions to perform operations for managing an oscillationamplification factor margin of the booster amplifier 400 as representedby one or more of blocks 1302, 1304, 1306, and 1308 of the method 1300.Although illustrated as discrete blocks, various blocks may be dividedinto additional blocks, combined into fewer blocks, or eliminated,depending on the desired implementation.

The method 1300 may begin at block 1302, where a wireless signal withina wireless network received by a booster amplifier may be amplified byan applied amplification factor. In block 1304, the appliedamplification factor may be increased by an amplification factoroscillation margin. In some embodiments, the amplification factoroscillation margin may result in at least an amplification oscillationmargin of three decibels.

In block 1306, it may be determined if the booster amplifier isoscillating when the applied amplification factor is increased by theamplification factor oscillation margin by checking for oscillations ofthe booster amplifier. In block 1308, the applied amplification factormay be adjusted based on whether the booster amplifier is oscillating tomaintain at least the amplification factor oscillation margin betweenthe applied amplification factor and an oscillation amplification factorthat causes oscillations in the booster amplifier.

In some embodiments, when the booster amplifier is oscillating theapplied amplification factor may be decreased. In some embodiments, theapplied amplification factor may be decreased by less than theamplification factor oscillation margin. In some embodiments, theapplied amplification factor may be decreased by more than theamplification factor oscillation margin.

In some embodiments, when the booster amplifier is not oscillating, theapplied amplification factor may be increased. In some embodiments, theincrease in the applied amplification factor may be less than theamplification factor oscillation margin.

One skilled in the art will appreciate that, for this and otherprocesses and methods disclosed herein, the functions performed in theprocesses and methods may be implemented in differing order.Furthermore, the outlined steps and operations are only provided asexamples, and some of the steps and operations may be optional, combinedinto fewer steps and operations, or expanded into additional steps andoperations without detracting from the essence of the disclosedembodiments.

For instance, detecting oscillation of the booster amplifier may furtherinclude sampling power of the wireless signal in the booster amplifiermultiple times over a period to obtain multiple power samples of thewireless signal and determining a power ratio of the wireless signalusing the multiple power samples of the wireless signal. Detectingoscillation of the booster amplifier may further include comparing thepower ratio of the wireless signal to a threshold power ratio that isbased on a configuration of the wireless network. Other methods ofdetecting oscillations of the booster amplifier as disclosed herein mayalso be used.

FIG. 14 is a flow chart of another example method 1400 of determining anoscillation amplification factor margin of a booster amplifier in awireless network, arranged in accordance with at least some embodimentsdescribed herein. The method 1400 may be implemented, in someembodiments, by a booster amplifier, such as the booster amplifier 400of FIG. 4. For instance, the microcontroller 414 of the boosteramplifier 400 of FIG. 4 may be configured to execute computerinstructions to perform operations for managing an oscillationamplification factor margin of the booster amplifier 400 as representedby one or more of blocks 1402, 1404, 1406, 1408, 1410, and 1412 of themethod 1400. Although illustrated as discrete blocks, various blocks maybe divided into additional blocks, combined into fewer blocks, oreliminated, depending on the desired implementation.

The method 1400 may begin at block 1402, where a wireless signal withina wireless network received by a booster amplifier may be amplified byan amplification factor. In block 1404, the amplification factor may beincreased by a first particular amount. The first particular amount mayamount to an amplification of at least three decibels in the boosteramplifier. In some embodiments, increasing the amplification factor bythe first particular amount may occur periodically.

In some embodiments, the first particular amount may be an amplificationfactor margin between an operational amplification factor of the boosteramplifier and an oscillation amplification factor of the boosteramplifier. The oscillation amplification factor of the booster amplifiermay be an amplification factor that causes the booster amplifier tooscillate. The operational amplification factor of the booster amplifiermay be an amplification factor that the booster amplifier applies amajority of the time to a signal. Note that the operationalamplification factor of the booster amplifier may be adjustedperiodically based on factors within the network as disclosed herein andfor other reasons.

In block 1406, oscillations of the booster amplifier when occurring maybe detected based on the sampled power of the wireless signal.

In block 1408, it may be determined if oscillations of the boosteramplifier occur when the amplification factor is increased by the firstparticular amount. When oscillations are occurring in the boosteramplifier due to the increase in the amplification factor by the firstparticular amount, block 1408 may be followed by block 1410. Whenoscillations are not occurring in the booster amplifier due to theincrease in the amplification factor by the first particular amount,block 1408 may be followed by block 1412.

In block 1410, the amplification factor applied to the wireless signalmay be reduced by a second particular amount that is greater than thefirst particular amount. In block 1412, the amplification factor appliedto the wireless signal may be reduced by a third particular amount thatis equal to or less than the first particular amount.

The embodiments of the present invention may comprise a special purposeor general-purpose computing device including various computer hardware.The control circuit or other processor included in embodiments of abooster amplifier are examples of a computing device.

Embodiments within the scope of the present invention also includecomputer-readable media for carrying or having computer-executableinstructions or data structures stored thereon. Such computer-readablemedia can be any available media that can be accessed by a generalpurpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise random accessmemory (RAM), read only memory (ROM), electronic erasable programmableread only memory (EEPROM), compact disk read only memory (CD-ROM) orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code means in the form of computer-executableinstructions or data structures and which can be accessed by a generalpurpose or special purpose computer. Combinations of the above shouldalso be included within the scope of computer-readable media.Computer-executable instructions comprise, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing device to perform a certain function orgroup of functions.

The following discussion is intended to provide a brief, generaldescription of a suitable computing environment in which the inventionmay be implemented. Although not required, the invention may bedescribed in the general context of computer-executable instructions,such as program modules, being executed by computers in networkenvironments. Generally, program modules include routines, programs,objects, components, data structures, etc. that perform particular tasksor implement particular abstract data types. Computer-executableinstructions, associated data structures, and program modules representexamples of the program code means for executing steps of the methodsdisclosed herein. The particular sequence of such executableinstructions or associated data structures represents examples ofcorresponding acts for implementing the functions described in suchsteps.

Those skilled in the art will appreciate that the invention may bepracticed in network computing environments with many types of computersystem configurations, including personal computers, hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network PCs, minicomputers, mainframe computers, and thelike. The invention may also be practiced in distributed computingenvironments where tasks are performed by local and remote processingdevices that are linked (either by hardwired links, wireless links, orby a combination of hardwired or wireless links) through acommunications network. In a distributed computing environment, programmodules may be located in both local and remote memory storage devices.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A method of determining an oscillationamplification margin of a booster amplifier within a wireless network,the method comprising: amplifying a wireless signal within a wirelessnetwork received by a booster amplifier by an amplification factor, theamplification factor being at a first applied amplification factor;checking for oscillation of the booster amplifier; when the boosteramplifier is not oscillating, reducing the first applied amplificationfactor by an amplification factor oscillation margin; and when thebooster amplifier is oscillating, reducing the first appliedamplification factor by a particular amount.
 2. The method of claim 1,wherein the particular amount is greater than, less than, or equal tothe amplification factor oscillation margin.
 3. The method of claim 1,wherein when the particular amount is greater than the amplificationfactor oscillation margin, the method further comprises: checking foroscillation of the booster amplifier when the amplification factor is ata second applied amplification factor less than the first appliedamplification factor; when the booster amplifier is not oscillating,increasing the amplification factor by the amplification factoroscillation margin; and rechecking for oscillation of the boosteramplifier after the increasing the amplification factor.
 4. The methodof claim 3, wherein the second applied amplification factor is greaterthan the first applied amplification factor reduced by the particularamount.
 5. The method of claim 1, further comprising maintaining atleast the amplification factor oscillation margin between theamplification factor and an oscillation amplification factor that causesoscillations in the booster amplifier.
 6. The method of claim 1, whereinthe amplification factor oscillation margin results in at least anamplification oscillation margin of three decibels.
 7. The method ofclaim 1, further comprising setting the amplification factor to thefirst applied amplification factor to maintain the amplification factoroscillation margin.
 8. The method of claim 1, wherein the amplificationfactor oscillation margin is varied based on one or more factorsassociated with the wireless network.
 9. The method of claim 1, whereinchecking for oscillation of the booster amplifier includes: samplingpower of the wireless signal in the booster amplifier a plurality oftimes over a period to obtain a plurality of power samples of thewireless signal; determining a power ratio of the wireless signal usingthe plurality of power samples of the wireless signal; and comparing thepower ratio of the wireless signal to a threshold power ratio that isbased on a configuration of the wireless network.
 10. A method ofdetermining an oscillation amplification margin of a booster amplifierwithin a wireless network, the method comprising: amplifying a wirelesssignal within a wireless network received by a booster amplifier by anapplied amplification factor; increasing the applied amplificationfactor by an amplification factor oscillation margin; checking for anoscillation of the booster amplifier when the applied amplificationfactor is increased by the amplification factor oscillation margin; andadjusting the applied amplification factor based on whether the boosteramplifier is oscillating when checked to maintain at least theamplification factor oscillation margin between the appliedamplification factor and an oscillation amplification factor that causesoscillations in the booster amplifier.
 11. The method of claim 10,wherein when checking for the oscillation of the booster amplifierindicates an oscillation of the booster amplifier, adjusting the appliedamplification includes decreasing the applied amplification factor. 12.The method of claim 11, wherein the decrease in the appliedamplification factor is less than the amplification factor oscillationmargin.
 13. The method of claim 11, wherein the decrease in the appliedamplification factor is more than the amplification factor oscillationmargin.
 14. The method of claim 10, wherein when checking for theoscillation of the booster amplifier does not indicate oscillation ofthe booster amplifier, adjusting the applied amplification includesincreasing the applied amplification factor.
 15. The method of claim 14,wherein the increase in the applied amplification factor is less thanthe amplification factor oscillation margin.
 16. The method of claim 10,wherein the amplification factor oscillation margin results in at leastan amplification oscillation margin of three decibels.
 17. The method ofclaim 10, wherein checking for the oscillation of the booster amplifierincludes: sampling power of the wireless signal within the boosteramplifier a plurality of times over a period to obtain a plurality ofpower samples of the wireless signal; determining a power ratio of thewireless signal using the plurality of power samples of the wirelesssignal; and comparing the power ratio of the wireless signal to athreshold power ratio that is based on a configuration of the wirelessnetwork.
 18. A method of determining an oscillation amplification marginof a booster amplifier within a wireless network, the method comprising:amplifying a wireless signal within a wireless network received by abooster amplifier by an amplification factor; increasing theamplification factor by a first amount; detecting whether oscillationsof the booster amplifier are occurring when the amplification factor isincreased by the first amount; when oscillations of the boosteramplifier occur when the amplification factor is increased by the firstamount, reducing the amplification factor applied to the wireless signalby a second amount that is greater than the first amount; and whenoscillations of the booster amplifier do not occur when theamplification factor is increased by the first amount, reducing theamplification factor applied to the wireless signal by a third amountthat is equal to or less than the first amount.
 19. The method of claim18, wherein the first amount is an amplification factor margin that isbetween an operational amplification factor of the booster amplifier andan oscillation amplification factor of the booster amplifier.
 20. Themethod of claim 18, wherein the first amount amounts to an amplificationof at least three decibels.